Git porcelain stuff's plenty good for probably 95% of users. `rebase -i` comes with a guide on which commands do what, and you could write a couple of paragraphs about how to format `git log`'s output with your own preferences and tradeoffs -- and porcelain usually includes stuff as eclectic as `git gc`, `git fsck`, and `git rev-parse` by most accounts.
Git plumbing's definitely a bit more obscure, and does a bunch of stuff on its own that you can't always easily do with porcelain commands because they're optimized for the common use cases.
TL;DR: while Git's big (huge even), a lot of what it provides is way off the beaten path for most devs.
tldr: even if you never plan to use anything advanced, you’ll end up in some weird situation where you need to do something even if you’re in the “95% of the users”
no shade, yes ofc you “could this, could that” to make things work and we have been stuck with this for so long that an alternative doesn’t even seem plausible
It did take maybe a year or so to develop the mental model of the how commands map to the underlying structure of commits, and another few years to avoid footguns (like always "push --force-with-lease").
So I think it is probably too complicated and would be happy to switch to a better alternative if one comes up, but what seems really implausible to me is going back to the bad old days of SVN.