Why would China's housing be in a bubble? This popular video on YouTube, &quot;China's Reckoning: Housing Crisis&quot;, suggests that the housing market in China is in a bubble, because the vacancy rate is very high.
However, it also acknowledges that there is no credit bubble like there was in the US.
I don't understand this argument. As the video claims, the Chinese are culturally &quot;obsessed&quot; with real estate, and buy houses even though no one lives in them, which drives up the price of real estate.
However, isn't this exactly what we have with gold? Most gold is not being used for anything productive. It's our cultural obsession with gold that keeps up its price. No one suggests that gold is in a bubble because of this.
This issue has been at the fore among China watchers for many years. While bubble classification is often subjective (even the Fed concedes):

[The] econometric detection of asset price bubbles cannot be achieved
with a satisfactory degree of certainty.

However, there is mainstream consensus that China's real estate sector likely has cause for concern. The below are not intended to be smoking guns, but may be useful heuristics for intuition：

Property developers are typically among the most leveraged operations
in China (leverage has been associated with previous &quot;bubbles&quot; like
US in 1929 and 2000.)
As you mentioned, property transactions as a result of speculation is
increasing versus organic demand from end-users of property
(also have divorce legal loopholes to acquire more real estate)

China began a deleveraging process several years ago but rebooting the economy after economic shutdown in 1Q20 required stimulus. However, recently, PBoC has been tapering liquidity after a banner year in financial assets and even some alternative assets (like real estate). As mentioned, leveraged companies often feel the brunt of a tightened liquidity environment first. China Fortune Land was perhaps the first casualty, defaulting on billions of dollars in 4Q20. A few days ago (at the time of writing) the financial media also picked up a similar situation unfolding with an even larger developer:
https://www.bloomberg.com/news/articles/2021-03-25/rating-cut-ignites-fresh-concern-over-chinese-real-estate-firms
Housing vs credit vs gold
To get at your question more directly, I think it's still fair to say that credit is at play here. The latest macro leverage figure from December 2020 prints 270% of GDP. (M6404532 is the code if you have a Wind financial terminal). Ultimately, this number plays a large role in guiding policy decisions. In the last year alone, property restrictions and land developer bond financing rules were tightened in an attempt to bring leverage down and cool the sector as a whole. Still, there is a lot of nuance and market quarks to be aware of here; this is where the 'art of policy' comes into play.
On the one hand, regulators want to preemptively de-risk the financial system and develeraging is one of several paths forward.
However on the other hand, real estate is a vital part of the fiscal income of many regional governments -- many of which have very troubled financial situations. Many provincial governments turn to non-standard credit to bolster their fiscal budget: real estate developers and other local SOEs are often the issuers. Global ratings agencies are not currently allowed to rate these local government financing vehicles, and local rating agencies tend to be rather generous, so this could explain partially the necessity and propensity of a 'bubble' to emerge and sustain itself.
The notion of 'cultural obsession' has its role too. After all, capital markets are somewhat new to China; the SSE has only been around for 30 years. We can see that the median investor portfolio tilts towards real estate more so than most:

However, after we peel back the financial engineering, China's housing bubble is not so different from the US experience. Or, it could arguably be characterized as a combination of cultural obsession and leverage.
Let's try and tie this to gold. Any bubble, again, as the Fed has conceded, is subjective. However, if we look at what prices reflect on the various portions of the economy, you could find conflicting signals.

In a reflationary scenario, or if deleveraging turns out to be
successful, the real estate and financial markets could march forward
into the next few years unscathed. This might suggest the bubble was
in gold.
Alternatively, if we view gold as a safe-haven asset and succeeds in
preserving wealth after a vicious correction, then life in a
rear-view mirror makes the bubble appear to be in assets (financials/alts).

Ultimately, if we subscribe to the belief that capital markets produce informative prices, then the prices in these different asset classes could reflect diverging views of the direction of the economy. Still, in a world of  momentum traders and Fed interventions, fundamentals aren't the only thing at play. For this reason we should pay attention to who is investing with stewardship or high-conviction from those who are trying to turn a quick buck. I'm sure there are plenty of speculators in the gold market.