Is roofing a useless task? I think not, we all need roofs. Have you ever personally replaced a roof in the middle of summer? I have. After that, I never thought of a climate controlled office as a place I was "stuck".
Each incremental reduction in friction and improvement in comfort feels good. But is the net effect happiness? I think it's anomie, in the limit.
Also if roofing was a non-problem anymore (we solved it somehow), would you want to have people doing it just for the sake of doing a job?