For a variety of reasons! I am autistic, and spend a significant part of my time unable to communicate verbally. However, since no one I know had any knowledge of BSL, and I didn't feel able to ask them to learn just for me, I didn't really see it as an option. However, I met a friend who is in a similar situation to me, who chose to learn anyway, and taught their parents rudimentary BSL themselves. This made me decide to try to do so as well, if only to communicate with them better as well. I feel it is also a very useful skill to have, and could be relevant to work I want to do in the future.
