It is, but not nearly all merchants accept Apple Pay or Google Pay.
Apple also seems to have no interest in letting other browsers on macOS use it, and I do most of my shopping on my mac, so I end up using my plain card number in almost all cases.
If the merchant seems particularly sketchy about security or not charging the card for more than what was agreed on (or makes it very hard to cancel their service), I need a one-time use card number anyway, since Apple and Google Pay don't yet protect against the latter.
Apple also seems to have no interest in letting other browsers on macOS use it, and I do most of my shopping on my mac, so I end up using my plain card number in almost all cases.
If the merchant seems particularly sketchy about security or not charging the card for more than what was agreed on (or makes it very hard to cancel their service), I need a one-time use card number anyway, since Apple and Google Pay don't yet protect against the latter.