Simply put, ease, and efficiency on my end. If I have too many IM services, then I am stuck juggling things around. Which service does this person use is a big issue. With that in mind, I use the minimum number of services, and don’t see value in using other services. For example, I don’t have Telegram, and therefore will not see me installing Telegram. The same will go with many other IM services despite on how popular they are globally.
For most contacts, I will use the IM services provided in this site. This is to keep things simple. I will not install any new IM service or clients though. As mentioned in this FAQ, I don’t want to have to juggle through multiple platforms because everyone is a little different.
If you have an Android smartphone, then your phone should support RCS. RCS uses data just like Telegram, and WhatsApp. You would use the Google Messages app on your Android phone. If you are using an iPhone, then you can send me an iMessage which again – uses data. It takes 1,000,000 characters to equal 1MB.