The main purpose of the app is to be spyware. The messaging & photo-taking aspect of it is secondary and is just there to give you a reason to install the spyware. If they could get people to install it without those features they wouldn't even bother developing them.

The same applies for most "free" apps (especially social media) and the reason why I don't use nor recommend anyone else uses them. I've tried hard to accept the nasty behaviour as a trade-off of the functionality the app provides but the downside always outweighed the upside.