everyone else has mentioned KYC options, so I'll go against the standard reply..
when you buy from any of these companies you're trusting them with your tax ID, name, address, phone number, etc. If any of these companies are hacked or compromised, how would this impact you? Knowing how much bitcoin you have, as well as a slew of other personally identifiable information.
Stacking Bitcoin privately NoKYC is more challenging and annoying; I'll concede that. But I strongly believe that this is protection from government 6102 type of executive order, or a hacker with a wrench that finds out who you are.
At the end of the day it comes down to the tradeoffs you are willing to make.
However the most important thing is to stack sats, however you're able.
