I don't think DWG is sealant-like. Yes it bonds to the paint, but I don't think it crosslinks like sealants do, which require usually 12-24 hours. If DWG crosslinks instantly, why haven't Menzerna and all the other companies made their sealants cure that quickly? I think that it bonds to the paint much like a wax does, just kind of grabbing onto it, not cross-linking. That is why it can be applied on top of a wax/sealant. And it can be topped by a sealant.
That said, I have it and love the gloss it provides. I have topped it with Natty's Red. Question though: Can you layer it? It can be applied on top of a sealant/wax, and a sealant/wax can be applied on top of it, but can it be applied on top of itself?
Note: I'm no expert, that's all just my speculation. Maybe Bob can chime in.