Supporting your LDS- local dive shop is a very good idea for the sake of tank rentals, dive clubs, and air fills.
Push come to shove, you can find your local Hydro facility and cut away the middle man. You can buy gear online and even service your gear by shipping it to another shop out of state or across country.
But you cannot plug your tank into a USB port and fill it. So for that purpose alone the LDS is a very useful being, unless you want to drop grands on a fill station compressor and it's maintenance.
If your shop simply doesn't have that type of gear you want to buy, at least support it with the small accessories purchases, even though you'll pay the higher price by a few bucks at most.
If you don't like the shop, give them constructive feedback. A good shop will not repulse to that unless you come off aggressive or they simply have a bad attitude, which does happen.