They have an extensive blacklist of VPNs, and on top of that will require you to verify location on a phone if you don't have an obvious residential IP. Or maybe they just always do that? Of course if you have a sketchy proxy and a phone where you can spoof location and you can ensure they don't flag it as something "unverified" like GrapheneOS, you can get around it, and you'd be in a small minority.

Unfortunately know this because a gambler friend showed me.

I've found that some sites (even like restaurants, for example) have no problem setting up an order when I connect via my VPN (from Linux) - my default browsing setup. But when I go to pay, their payment processor refuses to work properly / fails, so I can't actually transact any $$. Others work just fine WITH VPN on. Sadly, the former is increasing and the latter decreasing, to the point it's getting harder and harder.

Heck, Lowes and BestBuy are pretty unusable in general via VPN already.. (or maybe due to ublock, or privacy badger or eff, etc.. :-)