Well, yes. GUI usually don't require much algorithmic work so there's just not much space to loose performance because of bad algorithms.

But I've seen researchers been vastly prolific in Python. They make segmentation or registration algorithms that beet the market, and then they call us (C++ engineers) to make them "fast". Usually we do, since we're trained for that. But it's never orders of magnitude. It's like 2-3 times faster.

And there were even cases where the C++ code appeared slower in the end. Well, we use slightly different math core than the numpy does and sometimes they're doing worse.