Youbike seats are notoriously uncomfortable, probably due to the extreme heat they need to be, as well as to discourage users from riding too long(?).
I bought this padded seat as an add-on. It had the additional benefit of adding about 1cm to the seat height which on a Youbike really helps. Even for the short me, they’re too small. But is it more comfortable? Well, I tried it for 10 minutes. It didn’t make a difference. 10 minute rides are just too short. We’ll see.