It's not as widely accepted because it's tied to one board house. If you make designs in their software, you're locked into buying from them, and the PCBs aren't cheap at all. You can buy Gerbers from them, but for hobbyists this is terrible, it's $50 if you add a Gerber CD with PCBs, and unspecified money if you buy without PCBs. You won't be able to throw some Gerbers at BatchPCB or Seeedstudio and get good prototypes for under $30.
Eagle is worth the time investment to learn. Lots of hobby projects fit within the free size limitation, and it outputs standard Gerber files. If you want to start selling your projects, you can buy that same version for $50 and use it as much as you want. If you need larger PCBs or more copper layers, yeah it'll cost you a few hundred bucks. The autorouter is next to useless, so I only bought the professional layout and schematic modules for about $1k total.