I switched and we do use more acid. That is mainly due to our fill water having high TA and large amounts of evaporation in the hot Arizona summer. When I say "more" I mean about a 1/2 gallon of 31.45% MA a week. Keep in mind our fill water TA is 130, I have a 20K gal pool, the pool is in full sun, and the temperature is regularly above 105. If you don't have high TA or have a lower evaporation rate than I do, it will be easier to dial in your TA and you won't be battling ph. I've seen many post on here where SWG owners add acid very rarely.
Even if your fill water TA is a little high, consider that muriatic acid can be purchased at high concentrations and has a long shelf life. Liquid Chlorine is less concentrated and does expire. If you're worried about lugging gallons of MA instead of Chlorine, I'd guess you'll be lugging less MA with a SWG than you would be lugging gallons of Chlorine without one. These are just my anecdotal numbers, but I need to add about 64oz of MA to drop my pool from 8.0 to 7.5. I do that about once a week. So 2 gallons of MA lasts a month. Contrast that with the 1.5-2 ppm FC loss I experience daily. I need 32 oz of 12.5% Liquid Chlorine or 64 oz of household bleach a day to meet my chlorine needs. That works out to 7.5 gallons of 12.5% or 15 gallons of house hold bleach every month. I can make one trip to the local hardware store and get a month's supply of MA relatively easily. Before I had a SWG, I did weekly bleach runs.
Others may disagree with only adjusting pH weekly. People more knowledgeable than me will chime in. I've found that I can add acid and let the pH drift up over a week or so without negative consequence. On the contrary missing a chlorine addition for even a day or two can get you into trouble fast. For my money, the SWG is probably a little more expensive than manually adding chlorine, but it is a lot more convenient and forgiving.