here in the US in my situation it boils down to my parents/grandparents not being able to understand the difference between any texting application. I'm fine using SMS/iMessage because I know everyone has it. I'd say the vast majority of non-technologically savvy people I know are incapable or unsure how to use the basic functions of their phone (very few people I know in this category use their phone for calls and texts and the web browser; everything else is just unused for either lack of understanding or lack of interest).