A few years ago we introduced Javascript coding in Construct . It's consistently the most popular programming language in the world according to StackOverflow's...
So for me, fully switching to scripting means you could lose like 0-10% of engine features, depending on the game you are making (in most cases i really doubt you will lose anything, and even if you do, you can still use event sheet to avoid those limitations without much pain). At the same time, scripting gives you 300% more features and flexibility, so those 10% are easily compensated :)
Btw, do you mean there is no "on collision" event and testOverlap doesn't use collision cells for optimization? If so, yes, it is a limitation. One of my unfinished games was based around a lot of collisions, and even though i didn't really optimized it, it worked okay, so it depends on the game you are making.
I never really saw any feature requests of such optimization, so i don't think much people really needed it. Recently there was a discussion on collision cells and Ashley introduced condition cell size editing. I guess, we are not far from having those optimizations in code too.
(2/2)