Electric chisel from angle grinder - video

Electric chisel from angle grinder. By Diamleon Diy Builds. 11:40 video:

https://www.youtube.com/watch?v=cssikTKmvA4

I'd want to bolt that thing to a motor with speed control. A reciprocating saw seems like a better candidate than an angle grinder.

Also, is it mandatory to attach a chisel to the end? I'm asking for a friend.