I will continue to use iMessages for my iOS contacts. For SMS people I will gently nudge (hey, have you tried Signal? and then let the convo go where it does) and then use Signal as the primary for those people.
99.9% of messaging (for me) occurs via iMessages or SMS. FB Messenger is occasionally used for people who are more acquaintances (don't have their phone number).
I don't really have a good reason to not use iMessages (blue bubbles). Reasonably secure and Just Works. SMS on the other hand.... my least favorite part of SMS (besides the complete lack of security) is that media messages are crippled in quality. Photos and videos are compressed and distorted beyond belief.
not just android, they work with every mobile handset even with the poorest reception or (even lack of) data-plan.
i use ~200 sms per year, pretty constant since i got my first mobilephone.
kinda sad we didnt come up with something better thou.