Apps do all sorts of things, just like this, and we let them run in the background and see all of the other apps we have. They also get access to any location or contacts you allow.
Websites don't.
We use the GasBuddy website for quick prices, but never log in.
Apps all have backdoors and you agree to the 25 pages of legalese when you install.
Only an idiot signs up for this.