Glass coat is a process which doesn’t need any wax etc before being done. Its a process which should be gotten done professionally where they will prep the surface with different procedures such as claying, cutting, polish and base prep etc and then do the coating all in an indoor place.
Sealants are more like a wax and can be played with yourself once they are done.
On the other hand glass coating once done doesn’t chemically remain compatible with waxes etc. I like to keep playing later so for me sealant is the way to go. If I was a lazy person I would have gone for glass coating and then followed the maintenance coats every 6-9 months on it since maintainence of glass and ceramic coats again are better done professionally.
Maintainence of sealants is diy with waxes etc.
Glass coat obviously has a longer life than sealants and waxes. What I don’t like about glass coats is that you can’t exactly repair them like a pro and secondly if you need a repaint on any part God forbid, the paint matching from a coated surface might not be an accurate result for the new part.
With sealants I have the liberty of using compound and polish if needed which isn’t the case with glass coat because if you compound a certain mark or a piece, that area will be deprived of the coating and rest of the car will be coated. Glass coat doesn’t blend with diy stuff while sealant does.
I myself an an amateur to detailing and knowledge of these things so anyone who knows better is requested to correct me please and add to my knowledge 
@Rahat083144 might be having better know how than me and he can also help.
