Nope. The idea is that perf should be good enough that it's not necessary.
withoutboats and I are hopefully going to collaborate and add notty protocol support to Alacritty. This should make text splits as performant as GUI splits.
I (withoutboats) agree. The real problem in terminals is that this goes both ways - if you let tmux or just vim/emacs split the window, you get no GUI integration - but you use the GUI to split the terminal window, you now have two disconnected shell sections, so none of the CLI integration works.
The notty screen splitting protocol should support a "GUI" interface shared by a single process, solving this problem.
withoutboats and I are hopefully going to collaborate and add notty protocol support to Alacritty. This should make text splits as performant as GUI splits.