A while back I'd looked at the Little Shop rear disc kits and noted the same issues that has been discussed here. The caliper pins are not designed to take the braking load, they are only used in stock systems to allow the calipers to float. The load is taken from the knuckle / axle casting or an abutment bracket if its a more modern setup.
Something like the Pro Performance kit is closer. Note that the abutment bracket takes the load, which is then transferred back into the adapter bracket from the kit.
https://www.streettrucksmag.com/88-98-obs-chevy-disc-big-brake-conversion-freeman-fabrication/ I'm not saying the adapter bracket they provide is adequate as I haven't done any calculations on it.
The Little Shop kit seems to work, and will probably work for a while. At some point those caliper pins could possibly fatigue, break and you'll lose rear brakes. That is up to each person to take that risk, I'm not willing to do that. For brakes both my trucks (99 C1500 Suburban and 98 K1500 RCLB) have hydroboost / 3/4 ton front calipers with good pads and the 11" rear drums. They both stop great and use OEM parts.
Looks are subjective and I think you're overstating the weight differential between the discs and drums. Discs are lighter yes, but 200 lbs seems excessive. I'm not a huge fan of the parking brakes integrated into the caliper, over time it tends to seize up. Had to replace these on other cars several times for this issue.
Since the engineer thing keeps getting thrown around here, FWIW I am a degreed Mechanical Engineer with 15+ years design experience.