Why test so early?

I'm new to this app. This is my first month using it and I noticed alot of ladies take a hpt way before they missed their period. I've seen some pics with "faint lines" and some that are just not there and others comment they think they see something when clearly is not. Giving them false hopes. I don't understand why test so early. In most cases is such a disappointment. I've been TTC baby #3 for a tree and half, but I have only tested when I miss my af. I know everyone's body is different, but I just feel bad for those that test and test and test only to be let down instead of waiting until they miss af. Anyone else feel the same way?