Why isn't the moon's surface made of mini craters? I thought that the millions of mini rocks that hit the moon would cause it to be entirely cratered and not flat.
Why is the moon not like this:

why aren't craters visible in the footprint photo?
Nice question, unfortunately your analoguous experiment is not as analoguous as you might hope.
In your comparison image you are using both, not enough impactors, and a too tiny size distribution. Impactors on the Moon (or any other objects) follow a reasonably well-known size distribution where the smaller an impactor is, the more frequent collisions with those do occur.
The visible and measured / counted size distribution of craters on the Moon follows this probability law quite well (e.g. this paper (Cross, 1966), but many others get about identical results). The main difference is that in your comparison you miss all the very tiny impactors which smooth-out the surface again.
Further, the Moon is covered with loose regolith of about 45µm diameter. In the sunlight it is subject to charging and thus the Moon surface is covered by a tiny sheet of statically elevated particles. This leads to a re-distribution of the surface regolith particles, smoothing out the tiniest craters even more.
Even further, the landing sites of Apollo were carefully chosen to be the most level and crater-free places to ensure a safe landing. The amount of cratering in a particular place is also random, even when all the surface is covered by several layers of craters (this is a study for asteroids, but applies to other bodies, too).
And further more, your comparison experiment is conducted in air. That affects the formation of craters and in particular the distribution of ejecta due to friction with air, more so, the smaller the impactors get and the slower the ejecta are.