I can only be thankful that Colemak is supported on external keyboards on iPadOS, even though the virtual keyboard doesn't support it.
The hardware keyboard support is adequate for my needs (on iOS too, it's handy to fold open a Bluetooth keyboard to use with your phone) and I've never seen a need for Colemak in the software keyboards. I can't properly touch type on an iPad even if it supported Colemak because there's no "touch" there and I wouldn't want to accidentally ruin my touch typing skills with a "watch the keyboard" fake touch typing device. Easy enough to just have Bluetooth hardware keyboards handy. The iPad even has nice ones that attach by magnets and act as covers so they are always around.
Presumably people like us are exactly why it's included on external keyboards for iPadOS.
It is nice to have the consistency available. Though, I don't really have a need for it. Only case I can thing of is typing a few, key memorized passwords. I don't really remember the actual password, just the motions. Kind of a pain to motion it out and translate it to qwerty.