Most of them would benefit from learning to actually use it, but this is unfortunately niche.
I often go through list of recent commits and rebase them before sending PRs. That way, I save a bit of time not having to switch contexts with code and commit messages.
I personally like this format more because it lets you both be "dirty" in your branch writing commits for yourself, and not have to use amends/rebasing. I can see how it would be annoying for someone that does all the digging on the terminal through git log and blame, but we all use gitlab instead.
While we do not want you to leave ... :-) ... you'll have great tools to export your data from projects, for example https://docs.gitlab.com/ee/user/project/settings/import_expo...
Another way is to programmatically work with the REST API and export the needed data (https://docs.gitlab.com/ee/api/). This can be needed to specific backup and persistence routines for data compliance too. I personally recommend to use the Python, Ruby, etc. library bindings for easier API requests.
This won't solve the import into another tool, yet it opens a migration possibility with full access via an API.
Reviewing such a chunk in Gerrit is a PITA. It breaks up the flow of discussion and encourages a myopic perspective on the work.
I do not understand how people can live with only a single line for the commit message. For a new feature, I need to provide some details what is added and how it can be used. For a bugfix, a single line is rarely enough to describe the problem, what you changed, and why this change solves the problem.
Writing good commit messages is an essential part of using a version control system with a team. When trying to make the git interface easier, this should not be dumbed down. I would rather expect the tool to provide assistance with the usual format of a short subject and a body for a longer explanation.