Having only one courier back then was one of the things we can tell our children that they have a better life than us for those that didn't experience it.
As a Supp/Offlane, I miss the side shop. Being able to build Arcane boots without risking your life/waiting for courier is a blessing as a support. Also, sneakily buying Blink Dagger at the side shop has helped me escape multiple deaths, and making the safe lane cry with dagger + echo at 9-10mins lmao
I started to play dota 2 again recently and I was quite surprised to find the side shops removed, multiple couriers, outposts, neutral items, a new place for Rosh, and such.