"Use it or your social group will not want to interact with you"
option.
Outside of tech circles (where apparently people easily get their entire family and friend network on signal), people want to use imessage and only want to use imessage. Android phones can't support imessage because they are poor low quality phones that cannot handle imessage. So you need a high quality phone like iphone so you can use imessage and easily communicate with your friends and family.
This strategy of leveraging friends and family to pressure people into getting iPhones was intentional and came out in the Epic trial lawsuit.
I shit you not there is a large percentage of people in the US that think Android phones are not capable of sending pcitures and videos.