Low diameter and no stretch is great for softplastics at any depth and also deep water jigging or bait fishing. Also great when you need to fit more line on your reel. You do need mono backing and a leader. Line digging into the spool is a problem but can be avoided by packing the line tightly. That said, some reels are better suited to braid than others.
The advantages far outweigh the disadvantages for certain applications. What kind of fishing will you doing?
Run a search of this forum and you'll find plent more info.