Here's my two cents so far.

1.) It's fun, obviously, but I can see how people would sink a ton of cash into this if they weren't disciplined.
2.) I have a PSA sub and was offered a $25 credit. I added another ~150 in Ethereum since it's not real money.
3.) From that initial ~175 investment, I've opened 28 packs (mainly $100 Football Packs) and have instantly sold back 27 cards. You know, to rip more packs.
4.) My peak account value was ~700. Currently sitting at $108.
5.) I love the ability to sell back instantly. The prices seem far for the most part. It's 90% FMV then a 6% fee at the time of sale. Disclaimer, I'm not a football expert but I check against Terapeak. Seemed reasonable IMO.
6.) Honestly, I should have walked away and cashed out after hitting a Mahomes Cosmic Prizm (Sold at 474) but I've had fun chasing the next thing.
7.) All digital so no mess and my wife doesn't see a delivery box.