I purchased this for travel. I like the rfid lining, but Ill still be using rfid sleeves on my cards as well.
I put some items in this pouch (2 passports and cash...no phone or other bulky items) and wore it all day to simulate a day of traveling, and I was fairly surprised it was not hot. I got the beige for more transparency under clothes.
Wearing it high (just under the bra band) was ok, but somewhat noticeable. Wearable,  but not ideal...my second choice for wearing placement.
Worn low, under the belly was ok, just not as comfortable and constantly in the way...and seemed most noticeable under clothing. Im definitely not wanting extra bulk under the belly. People might just think I was chunky, the bulge didn't scream money belt!
On a hunch, I put it across the small of my back and that will be the best position for me. The pouch seems to be invisible in the slight curve of my back, and was very comfortable. I wasn't planning to get into the pouch frequently during my traveling days, but more for of a secret stash for cash I don't want to leave in a hotel safe. Im looking for discretion and not particularly easy access...hopefully that makes sense.
For under-clothing wear, one passport and cash/cards is perfect. Two passports fit, but overlap. Passports don't stand up straight, the pouch would need to be maybe 1/4 to 1/2 taller...not much at all. Passports must be sideways, as in the picture, and two don't fit end-to-end. The overlap adds a lot of bulk under clothes.
While wearing it, I had a dear friend (whos also traveling with me on my upcoming trip) hug me. She didn't even feel the money belt under my clothes!  I told her to try and find it on my back and she was amazed!  She asked to also wear it for a day and she loved it, so I got her one as well.
I love the three individual inside pockets for credit cards, and Ill have American cash and Euros in the other two pockets!  Makes me happy 
The sellers photo shows phone and earbuds, that would be ok if worn over clothes, but would be a horrid bulge under clothes. Depends on how you're planning to wear it, but a phone would easily fit.
The belt is easily adjustable and the clasp seems durable, doesnt unsnap on its own. Im happy with my purchase.