Qt costs serious money if you go commercial. That might not be important for a hobby project, but lowers the enthusiasm for using the stack since the big players won't use it unless other considerations compel them.
Depends on the modules and features you use, or where you're deploying, otherwise it's free if you can adhere to the LGPL. Just make it so users can drop in their own Qt libs.
QT only costs money if you want access to their custom tooling or insist on static linking. We're comparing to electron here. Why do you need to static link? And why can't you write QML in your text editor of choice and get on with life?
Some widgets and modules, like Qt Charts (or Graphs, I forget), are dual GPL and commercially licensed, so it's a bit more complicated than that. You also need a commercial license for automotive and embedded deployments.
> You generally can't adhere to the LGPL in automotive
"Can't" or "won't"?
The UI process is not usually the part that need certification.
> Slint has a similar license
Indeed, but Slint's open source license is the GPL and not the LGPL. And its more permissive license is made for desktop apps and explicitly forbid embedded (so automotive)
