I had most things that I needed at that point; a bed, a desk, an armchair, a bathroom and some storage. The 19.5 m² do not include the group kitchen which I shared with seven other people.
Regarding the size of my current apartment, I truly don't need more at this point in my life and I don't even use all the space that I have, it's not cramped at all. I can't come up with anything I would truly need, that I don't already have; there's not even more than a handful of things that I want.
I grew up in a 300 m² house of five; three the last few years I lived there. What did the space consist of? Unnecessarily many rooms, unnecessarily large rooms, unnecessarily long corridors, an unnecessarily large basement and unnecessarily much of everything in order to be able to have many guests over - useful at times, sure, but unnecessary most of the time. Living in a small apartment can be problematic when having many guests over or if you like to hoard on stuff, but it works great most of the time. What does one really need and use on a regular basis, anyway?
Thank you! I do like to keep things clean - although it's unusually clean in those pictures, as I had just finished moving in.
A mechanical version would be great and I agree, the G15 V2 wasn't really that good.