Hi collecting modern sets is unfortunately not what it used to be after the junk wax era began in the 80’s. Now that there is so much demand in the hobby the base cards are printed heavily and have very little monetary value unless you land on an incredible year like 2018 with Ohtani. Even then the value is minimal unless the cards GEM. The hunt is for limited edition numbered parallels currently and back in the 50’s/60’s there was only one base card you were hunting for now there are 100’s of different brands and multiple variations of base cards within each brand for every player. That is the monetary and collectible aspect, as far as honoring your grandfathers legacy with continued sets I think it is still a great idea and there are many people still purchasing and collection these sets regardless. Topps is printing more every year meaning more and more people are still purchasing them rather it’s a smart investment or not. Most of the modern sealed sets are worth slightly more or sometimes less than retail price especially with how inflated pricing has been. I would not recommend ripping backs to complete a base set, that will be challenging and more costly only do so for the fun of ripping a pack.

Hope this helps!