I'll put forth that yours is shorter, not necessarily simpler 😃 (the current implementation does fewer operations)
Yours is slower for arguments <1K. The performance draws even with arguments of around 100K (at least in my very quick and limited testing). This is probably explained by the computation of (⍳,-+⍳) taking less of the overall time with larger arguments.
So, in this case, I think I'll leave things as they are. (but I do like your solution!)
https://github.com/Dyalog/Jarvis/blob/4c23d762715c797e0bf8e9320c422fd4545238d0/Source/Jarvis.dyalog#L1723 can be simplified to
same goes for HttpCommand: https://github.com/Dyalog/HttpCommand/blob/2659ea89357f85cbe10d38797500c629c1f2cb8b/source/HttpCommand.dyalog#L958