I didn’t think I’d like it but after playing around with it for a day, I prefer it 
As I said here 
But as for it being “a little iOSy” I agree but disagree at the same time.
The bottom navigation is defined in Google’s Material.io guidelines
As long as it’s implemented correctly (which I can’t say if it is or isn’t) then I’m more than happy with what Monzo is doing