Love that technique! Very clever! I've never filled holes that way, seems like it works really well!
As I said, this is my version, a possibility of many, perhaps it is difficult to apply it in some places and for much larger or too small holes, it requires caution and a lot of practice for good results!
There is no "wrong" way to build a model if you`re having fun.
Now go, build a showrod model, show your work with pride and inspire others!