ELI5 - Real life implications of no privacy from apps like TikTok

This is a legit question I'm asking out of ignorance. I'd like to do a risk/benefit analysis but I need to know the actual risks to me and my well-being to do so.

What are the real life consequences of, say, TikTok having access to the things it does? I'm going to use TikTok because I think it's on the extreme end of the spectrum with privacy violations and would yield the most severe consequences.

So, they have all the …

apps life no privacy privacy tiktok