I created a bunnymark behavior just to compare the performance of plugins to event sheets - and the plugin was 3x as as fast as using events. So... There is an overhead to the event system. The trade-off, of course, is event sheet convenience - if no one notices the overhead then it doesn't matter....
Edit - this plugin was for c2 although it's likely the same for c3; I didn't check the forum title..!
We were mostly talking about the speed of coding, since more complex things are faster to do in visual events it's probably faster, although I guess more keyboard shortcuts while eventing never hurts.
That said, it's an impressive performance difference ditching the events. The runtime really should be pre-baked with the plugin/game code into one program on export, rather than interpreting the events IMO.
Otherwise, all Construct 2/3 is would be a fancy JSON editor if you can just grab c2runtime.js and slap your own data JS file with its HTML loader.