Of course it's worthwhile. On a round to round basis, the price per shot is wildly cheaper. The only real question is how long it will take to amortize the cost of the equipment. Shoot a lot and it happens faster.
I load and reload for more than 30 different cartridges and shotshells. Just considering the .45 ACP, I've loaded more than 60,000 rounds of it over the past bunch of years. I also cast my own bullets and so the cost per box is very low, down about $2.00 to $2.50 a box of 50. (I don't consider the cost of brass since with target ammo the cases can be used so many times that it's silly - and I keep finding the stuff that those "box from Walmart" shooters leave behind). Same thing, essentially, with .30-06 and .223 - though the powder costs more and jacketed bullets also. Maybe at this point they are about .25 a piece for .30-06 ($5 a box for ammo as good or better than the factory. And it's in stock. My actual cost is lower because people that I know who don't want to reload any longer keep giving me components - like .30 cal. bullets and powder and primers.).
What do shotgun slugs cost? About a buck a piece for your basic smoothbore punkin ball. I reload slugs that work as well as the factory stuff for the cost of the primer and powder (about 12-15 cents per shell). Cast the slugs.
Some things that I load for - a couple of wildcats and antique cartridges - cannot be purchased anywhere.
Is it worth it? You bet.
Pete