I play several musical instruments, most of them poorly, one or two fairly well. I am convinced that playing various instruments deepens musical perspective. When I go to strike a drum I might imagine I'm playing piano or singing. That imagination then impacts the decisions I make while drumming. There are obvious disadvantages to having so little technique too. For example, it's unlikely I will land any gigs on these instruments nor will I be included in a music magazine's shredder of the year list. The former has professional/financial implications while the latter has associated fallout in the realm of self-confidence, maybe. And sometimes a given musical idea that sounds good in mind emerges as a train wreck because I have so few chops. Still I persist.
As I hack at piano, guitar, melodica, vocals, synths, or bass, I wonder what I'm doing with my time. This wonder leads down many other pathways of thought, some inspiring and others quite dark. Inspiring: I'm trying to make sense of something in music other than mastery of an instrument. I'm trying to hone in on an approach beyond my physical relationship with a given instrument, something other than the athletic achievement of muscle memory and dexterity. Maybe that reads as pretentious but in reality there are many different perspectives and approaches to inhabit when playing music.
It's often said that each of us has a musical voice and that your specific voice will work itself out as a result of what you study, take in, embody. I believe that is true. But having a voice is separate from having something to say with that voice. In addition to the benefit of wider/deeper hearing that I mentioned above, I think that playing instruments poorly (with determination) is also a means of honing the something to say part. When you don't have much to lean on, a different type of focus emerges.