Stock or S-10 frame? Please explain why use an S-10 frame..

[FarmerSid]

New here and have a lead on a 53 3100. Being here reading all I can. Couple questions... I see so many of these trucks done with an s-10 frame. I still don't see the plus of the s10 compared to just adding a mustang II front end to the stock frame. I'm in eastern Ontario, Canada and don't see any older S10's for sale very much and if I do, they are in the $2000 range. Then I would have an S10 body and 53 frame left over. The money I would have invested in a old S10 I could just invest in a IFS kit for the stock frame. Am I missing something? I'd be fine doing a build either way but need to know everything as to why to do a frame swap. I understand S10 parts are easy to get at parts stores an all but wouldn't the ones from a mustang II be as well?

Thanks for the help!

Sid