Yeah, I think in canon the curvy bit at the front of the ship (or the nacelles, sometimes) is just gathering dust to then burn into energy. It gets trickier with the transporter, because in theory the dust is going into a matter/antimatter thing, but if the transporter is fueling itself from the body it's disintegrating... well, where's the antimatter?

I think in their minds the transporter isn't doing that, and is instead taking energy to both turn a person into a pattern and then build the pattern back into a person. Seems like a waste, but I guess the raw matter isn't the real concern here.