Those 2 directories implies a lot of complex things we don't want to promote "by default". It's the main driver for having "nss & co" so people can have unix account on system etc.
It's a bad thing from a security standpoint, it's a bad thing from maintenance point of view, it adds un-necessary complexity.
In this first step, we want to be able to install a platform without those /home stuff and to activate it by default for tuleap-aio docker image. Later when we will have enough feedback it will be activated by default for all install