Yeah thats an old example, now i not use pick or overlaping, get the XY hit point via LineOfSight and apply erase tiles with a radius formula to make a hole.
Due as Ashley said , tilemap is not made for that, then will be great some plugin or behaviour on C3 to add destructible terrain to any sprite/tilebackground or whatever.
So a focused object/bahviour with options to config as needed will be great, if the tilemap seamless thing is not possible on C3.
In C2 with the tilemap trick i was able to do this , and FPS at 60 with low CPU usage: i.imgur.com/4fVcTRj.gif . Now in C3 that is imposible.
I found some JS script about destructible terrain here:
And this one looks good too, on removing the terraing without nothing underhim goes down for a more realistic platformer: