I think of the cover as more of a dock.
Watching this review (in Portugese, so all I can do is watch, and ignore the audio) the Oasis connects quite easily to the cover. So I figure I will read a naked Oasis for the ergonomics and light weight, and attach it to the cover every night to allow it to recharge.
I have arthritis issues too, so I think the Oasis will help; both its weight and its real buttons. But I'm not a "buy the first day" person, so I'll try to wait a month to order. If I can resist!
PS I already have a Voyage.