[david-given]

Regarding deployment via a single executable: that's only true if your application consists solely of code (or resources which can be deployed in code, such as XBMs). As soon as you start having resources which aren't code, you end up having to deploy them as well, which means you have to start versioning them, etc, etc. The version of Chrome I'm typing this into is 120 files, one of which is the executable.

Regarding faster execution time: that's debatable. You certainly won't necessarily get faster application startup, because you're going to have to page in all that code, where with a DLL it's probably already in memory and used by another process. You're also likely to use a lot more memory, because each process will have its own Qt instance, and they won't be shareable.

Re RTTI and exceptions: works for me on Linux! Does this really not work on Windows?

Re whole code optimisation: that I'll grant you. And DLL code is typically terrible (because of hacks needed to allow text pages to be shared between processes).