Typically I have 3-4 different projects open at a time and probably 30-40 terminal windows across them and other places (in Ghostty).
Honestly it had never really crossed my mind that people used the built-in terminal for anything!
In other words, I don't care about the memory use.
I think I commented earlier that there's not that much I use the terminal for during development - mainly git. Keeping a terminal open, mainly hidden, in the bottom-left corner with the tab set to the top-level directory isn't really a burden.