I haven't looked at the project being discussed, but assuming it stores your code encrypted in some hosted git, one usecase I can think of is to protect the code from the hosting platform. For e.g. Microsoft ToS for Github allows it to scan / read your code for various kinds of analysis, which some may not want given their history of abuse. Encrypted git can prevent such things. And ofcourse, if one of the BigTech is going to be your competitor it makes to store your data encrypted on their platforms.