Sometimes you have a high key that you want to save for when your buddies get on so if you want to make your own groups it’s basically not an option if you want to save that key, it would be nice to have an alternative key that you can do those things with without burning the key you want to save for later.
Sure you could join a random group but for a lot of players it’s way faster to just make your own groups instead of signing up to LFG keys for 30-60 mins.
You need to not be so terrified of PvE and just play. If your key busts it busts, just find another group to carry your key up if you have such little confidence in your own abilities.
You missed the point entirely, it’s not about “being scared” it’s about being able to hold certain keys, maybe your buddy needs a certain key for mythic+ score or a certain drop or maybe you need crests from lower dungeons. There are so many good reasons you might want to hold a key for a later time. The fact that you don’t understand this tells me you’re a noob.
I’ve never seen a competent player terrified to put a key in. I’ve seen plenty of players needing carries worry over that. Which one do you sound like?