I received one similar to this as a gift. It's been working fine for me. It's not too slippery, non-scratching, and bits of things that might scratch the guitar's finish are easy to spot and wipe away. I don't have a bench set up full-time to work on guitars, so having something I can store out of the way is great.
$50 for a $10 Chinese tool kit ????
The issue with carpet and foams, is that bits of solder, string & wire clippings, etc., get embedded in them and they are hard to spot. If you lay a guitar on them, they will scratch the finish. Also, many of the foams will react with lacquer finishes and discolour them. The foam on my guitar stands reacted with the lacquer on my 87 LPC and left orange marks. Grant it, that happens over time.
You don't leave it on there long enough to react and the vast majority of guitars don't anyway, and you can shake out the carpet piece. Real techs have been doing this for decades.
Meh...It's the price of a few drinks at the bar. It's small and fits in my gig bag. I've had it for years so for me, it has been worth the expense.