Playing 2 instruments?

I have been playing guitar for nearly 2 years. I can write my own stuff and the only songs i know are Hendrix. These past two weeks i found a keyboard my lil sister got for xmas a couple years back and decided to plug it in and try and learn a few songs. I learned fur elise in 3 days even the harder middle section and then i just got done learning Turkish March (Mozart) in about a week. I learned these songs so much more quickly than anything i learned on guitar and i was wondering whether i should stop playing guitar and concentrate just on piano? Is it bad that i practice two instruments or does it have its benefits, or both?