According to https://www.puzzle-shakashaka.com/ the rules are basically the same (except that the numbers count empty cells instead of colored triangles, but that doesn't affect the puzzling, just the appearance). Or am I missing something?
Yes, essentially the clues in this version indicate number of available edges-triangles. We are used to counting triangles. The difference really is about convenience. Logic remains more or less the same.
I understand that it is inconvenient to switch once you're used to the other convention.
There was a discussion about this exact topic when the genre was implemented, and at that point it was decided to go with this meaning, because the rectangles catch the eye more.
It's unfortunate our conventions are different than the standard ruleset.