What I don't care for with the hose vac is twofold.
First, the hose makes it difficult to get around and is always pulling or hitting my head (I'm barely taller than the pool, have taken to wearing heels to vacuum or my arms go numb from hanging over the rail). Hauling the hose all the way around the pool in our small yard navigating obstacles (bbq, pond, garden, etc.) is a PITA, the hosebib is only 10 feet from the pool.
Second, when I replace water I want to know how much I'm replacing. Since I can lose significant CYA and Borates within a short amount of time with this method, within a few weeks everything could change dramatically. Difference between 30 and 40ppm CYA is only 25% of my water, which is just over 1300 gallons. Vacuuming for 25 minutes likely adds 5-10% each time (our water pressure is amazing, I can fill the pool in 3 hours with two hoses). In this case, it's possible that a week of every day vacuuming would pull CYA to 30 right quick, which changes minimum and target numbers from 3/7 to 2/5. Before, with the trichlor pucks that probably didn't matter so much but with BBB it wouldn't work well IMO.
When this occurs, as it will with normal splash out. I want to know how much water I replace, and when I did it. The self contained vac helps with long term clarity because I can vac every day if I want and nothing changes till I decide it's going to change.