I see a lot of questions from people about wheelchairs/
ECV's for mobility and stamina issues when being seated for a prolonged period also causes issues. A lot of times they want a DAS instead.
From what I understand, Disney is now enforcing the wheelchair/ECV as an accommodation for stamina and mobility, and if you don't want to use one, that is your choice Disney doesn't have to give you a DAS because you don't want to use the accommodation they have offered.
Just because you have a wheelchair/ECV doesn't mean you are chained to it all day. You can stand and walk when you need to, even in line. So what if you get dirty looks or comments? You can leave the device in stroller parking if you don't need it for a while.
Now if there is another reason you can't stand/sit/wait in line, then you should by all means explain your needed accommodations to GS and ask for a DAS. But just having pain or stiffness from sitting or standing still is probably not going to get you a DAS and I think that is unclear in some of the posts.