How long of a useful life are you looking to get out of this tabletop? How severe will the wear and tear be?

If you're looking for something to last decades or stand up to heavy use, I think there's no question that you need dowels/biscuits/whatever. Humidity and temperature changes are going to affect the bond between the glue and boards long-term, and the lateral pressure of heavy weight or motion will eventually be too much for that bond too.

If you just want to make something useful and nice while practicing your skills, don't plan to have it support any real weight, and fully expect to transform it or cannibalize it for parts eventually, then probably just glue will do.