It can be a huge concern just like what is happening with paypal. Paypal is taking the money of lot of users by putting hold on their accounts when they have become popular.
In fairness to PayPal, despite that there have been bad experiences that I've read about them, I've never got any problem with them. Honestly, I've made two accounts there because the first one was totally forgotten and it was more than a decade ago since I've logged back. After making the 2nd account there, they've asked me for some details not literally a KYC but connected my bank accounts and I'm good to go. I've seen concerns about them being blocked by PayPal but they're giving a period of time for them to return the money but they'll never be able to use the service again. Compared to the questioning of Binance about source of funds, they've never asked me that but it's been a while since I've used them again.