Cob
You brought up a slightly older thread, and there was another in the past year very close to this. Here is the link.
https://sawmillcreek.org/showthread....chtop-mortiser
Whether or not a Domino would be more useful than a bench top mortiser is a question that each individual would have to answer based on project types.
Other than the fact that each make a "mortise". I don't really see them as performing the same function. The domino is a true "floating tenon system with a size limitation. ( There is only so deep a mortise that can be made with a Domino. The bench top, or floor standing mortiser can make a much bigger, deeper, mortise. If you were making deep, structural, load bearing M&T joints, like interior and exterior doors, the dedicated mortiser would be the better choice. For cabinets and furniture project where overall size is a limitation to start with, the Domino can make very strong floating tenon joints,relative to size. It can do these family quickly and in place.
I have a Bench top mortiser, an older Delta 14-651, and would not be without it. I do not own a Domino only because I have made too many router jigs through the years that replicate it's core function. It's just a matter of economics for me, but you can be certain that if someone ever gave me one, I'd use it instead of a router with edge guides and jigs in a skinny minute.