This ^
The key things to consider are this -
1. They offer hearing protection, enabling you to have monitoring at a safe level
2.They offer an enhanced clarity over traditional monitoring solutions, you only hear what you want to hear, with minimal influence from ambient sound
3. You can move around the stage without impacting what you hear
4. They are a lot easier to carry around than a pair or wedges or rig (see them as a replacement for your rig, or monitor wedges, or both - and then you'll see that comparatively, they are cheap... and your back will thank you for it)
5. They enable you to go ampless
6. They enable consistency across gigs
7. They look cool as fk and makes it look like you mean business
@Hammer_If you haven't already, check out the following thread - https://www.basschat.co.uk/topic/389429-the-iem-bible-thread/ - all the advantages and tricks and tips are cleared off in there.