The QT licensing seems very anti-learning, because afaik anything you develop with it can only be commercial if and only if its entire development was done while using a commercial license.
Ethics aside, if you’re new to QT, play around with it using the non-commercial license (since you obviously wouldn’t know at that point if you could do something commercially viable) but you end up developing some rough prototype that might be a worthwhile stepping stone to a commercial product, and then at that point you buy a commercial license, could QT tell if you incorporate parts which were developed before having the commercial license?
That’s all changed now with the LGPL version, you even get the Visual studio integration tools for free.
The only reason for the commercial license is if you need commercial support or you are shipping on an embedded platform like a cellphone
Edit: As SigTerm points out, you do need the commercial license if you want to make changes to the Qt core and NOT return those changes to Nokia.