Bitboards vs. Mailboxes in the Era of NNUE...

[hgm]

Thats what I mean - the capture generator is much faster with bitboards: Visibility & Enemy
With mailslot you would need an if for every possible target square.
Less registers and memory needed than 64 slots together with faster code is everything you mentioned above - but the point is actually for BB.

Not at all. You assume that all moves are generated, and then have to be tested for being a capture. But that is not the way how it works. You only generate the captures, by extracting bits from the attackers set of the victim. And you would only do that for victims that are not empty square.