I've traveled to quite a few, and I'm always asked for passport (even if it's for a pay-as-you-go) while being there even for as little as for a couple of days.

I've traveled to quite a few, and I'm always asked for passport (even if it's for a pay-as-you-go) while being there even for as little as for a couple of days. I'm a white male, so it's not racism. Perhaps they skip the ID check on some cases, but don't they need a copy for documentation/first issuance?