Seeking info on turning my garage into another bedroom.

[Andy Eakes]

Hello! I live in a 1930s California Bungalow with an old detached garage too small to fit a modern car. My girlfriend and I thought about converting the space into another bedroom/laundry room as the space is only used for laundry and paint storage. There is also only an exterior wall. Would it be worth putting in an interior wall, some carpet, a side door, and improving the overall space? Or would it not add any value to the home? We have considered turning it into an ADU, but I am not sure if it is even big enough for that. Thanks in advance!!