Fishing is fun, easy, and a decent way to make money and get exp. What's more is that in Earth, you can fish at your base while ores smelt to get salvaging, mining, and fishing exp, all at once.
This is a good way to gain McMMo exp for prestige and lb (leaderboards). It's efficient if your on a low taming, fishing, smelting etc skill, so you'll basically go out of the roof with your new found skills and perks. As long as you don't macro or afk fishing in any way, skills would come in faster then Shrek riding a donkey.