The main purpose of PWAs is not to remove the browser toolbar but rather cache most of the website to improve speed and reduce data usage if I am not wrong, there are external tools to get rid of the toolbar but Firefox dropped the PWA spec which includes a lot more than just that.
They open in a window separate from the browser and don’t display the browser toolbar, so not just shortcuts.
The main purpose of PWAs is not to remove the browser toolbar but rather cache most of the website to improve speed and reduce data usage if I am not wrong, there are external tools to get rid of the toolbar but Firefox dropped the PWA spec which includes a lot more than just that.
The caching is the result of service workers which Firefox definitely supports.
edit: oh just scrolled down and saw you already commented that later.