The accommodation supplied by DAS is the ability to wait outside of the regular lines. It doesn’t shorten the wait, provide a place to sit inside or outside of lines or (in most cases) shorten the distance walked in the line.
Since DAS is for guests whose disabilities prevent them from waiting in the regular lines, that is what needs to be discussed with Guest Relations.
DAS is not needed to use a mobility device in lines/attractions.
My FIL and MIL came with us every year to WDW until the year he died. He had bad osteoarthritis in both knees and hips. Over the years, we saw his world at WDW shrink as his ability to move easily and without pain increased.
Our daughter has cerebral palsy (with other non-mobility related disabilities) and used GAC (Guest Assistance Card - the accommodation before DAS), so he could come with us and get in attractions in the easiest way. His last few trips to MK, he used the trolley car to get from the Main St hub to the Castle hub, then walked to Small World and Haunted Mansion. The rest of the day, he sat on a bench while the rest of us did things. He said he enjoyed sitting on benches and people watching, but we knew it was because that was all he was able to do. His day ended early, with pain killers and ice back at the resort from early evening until bed.
He tried to hide it, but we could all see his pain and it hurt us to know he was in pain and was not able to enjoy WDW with his family. We suggested an ECV and even rented one from an offsite company one year that he refused to use because he ‘didn‘t need it’.
A couple years before he died, he finally rented one at the park at Epcot.
Previously, he had walked in from the bus, then sat and rested, then walked thru Future World with a rest whenever he saw a bench, walked to the first Friendship boat dock in World Showcase (WS) and took the boat to the other part of WS and walked the area between the Italy dock (closed now?) and the dock near Morocco.
That trip when he finally rented an ECV was the first in years where he got all around WS and got to see everything he wanted to see. It was also the first time in years he had been able to stay at the park late enough to watch Illuminations.
He told us that night it was the first night in years that he had not ended exhausted and in pain by supper time. And, he said he could not believe how silly he had been to refuse to use one. He said wished he had used one the first time we had suggested, but since he didn’t use one every day, he hadn’t thought he was ‘disabled enough’.
After that, he rented an ECV at every park except MK (he felt there it was too busy and congested for him to feel comfortable driving there).