It's honestly a complete travesty. Strongly considering ditching my iPhone for the upcoming Pixel Fold or whatever it'll be called.
i would not for the life of me trust google with a 1st attempt at any hardware implementation. especially with one that will be pretty expensive
//Edit: Would really like to know for what I got down voted for?
Therefore, I have the impression that this is not a feature Apple would endorse much.
It's just less secure to use them than the one built into the OS because the third party keyboards might run input through some web service instead of keeping it completely local.