If you're an artist and don't play an instrument at least passably well, you're putting yourself at a huge disadvantage. There are exceptions, of course — if you're the lead singer in a band or have your own backing band, you may find it entirely unnecessary to learn an instrument.
This has it's own pitfalls, however. Keeping a band together is often hard work. Egos, conflicting musical tastes, and personalities are often more than a match for the most talented of bands. This is not to mention the added expense of paying band members.
Outside of the perfect scenario where you have endless money to pay a backing band and have a ready-made band of great musicians who are drug and problem free, you'll need to consider picking up a guitar at the very least. Here are just a few reasons why it's smart to learn an instrument if you're an artist.