Qt with HTML5 or without HTML5

Question

I've been programming with Qt libraries for 3 years. All programs have been designed by traditional widgets so far. But now I noticed that you can design your user interface with HTML5+CSS+jQuery. Now these are my Questions:

1. When should we design our interface with HTML5 and the core with Qt libraries?
2. What will be the advantages if we use HTML5 in designing user interface instead of traditional widgets?
3. Would it be reasonable if we design even our ordinary desktop applications user interface with HTML5?

Thanks!

Answer 1

1. There are no rules about "when we should". However there are some caseses when "we would" use it. For example we would use it if we want to make C++ developers focus on core functionality not gui. We could use some webdesigners then to create interface
2. Main advantage is that C++ developers don't have to focus on UI at all (well, some slight "integration" between HTML ui and C++ core would be required)
3. Everything depends on experience you want to give to user. If you want to give "native look'n'feel" Qt does most of the work for you with widgets. If you want to give "fancy look'n'feel" then you could use HTML. I don't see anything "unreasonable" in both ways of delivering user interfaces.