"Scrim shield" tape is designed for use on RVs (and boats, mobile homes, etc). It's a woven fabric material that looks like the Darco fabric used underneath an RV. Has a very aggressive adhesive that lasts. Won't tear easily like Gorilla tape. It's only available in 180' rolls (AFAIK) and rather expensive though. I bought a few feet of it from an RV dealer for emergency repairs for a couple of $$.
Gorilla tape is waaay cheaper and is probably the number 1 reason a dealer would use it and why owners would use it as well. Gorilla doesn't say their tape is waterproof but has this to say "We’ve found that Gorilla Tape will last a lot longer than regular duct tapes when it comes in contact with moisture". Scrim tape on the other hand is waterproof according to the manufacturer.
I'd rather use the right product for the application rather than a all-purpose, one-size-fits-all one. If you use either tape on the coroplast underbelly material, don't expect it to last very long.