TL;DR: if you want window decorations, link with libadwaita.
SDL ended up linking with libdecor. You know how when you use a Qt app in Gnome, it looks out of place? Now even the window decorations look inconsistent from one another.
For that reason alone I avoid Qt apps, as almost none draw their own title bar. Qt apps aren't even consistent among themselves in theming/style, for example the only apps that look in place on KDE are specifically made with KDE in mind.
I don't understand where the "consistency" obsession comes from, all these apps use different tool kits and will look different regardless.
Mental overhead. Sometimes Preferences is Ctrl-P, sometimes Ctrl-[,]; sometimes Copy is Ctrl-C, sometimes Ctrl-Shift-C. Sometimes the menu is a hamburger, sometimes a bar. macOS has none of these problems.
They're not a trillion dollar company. Sure, many projects would do well with more decisive decision-making, but the strength of free software comes from community and collaboration.