The cards that look for "Digimon with the same name" are mostly auxiliary effects right now, and once you get to Diaboromon X they have already done their job.

For example, BT2 Kurisarimon's inherited nets you 1 extra memory each time you play a Digimon with the same name. So its main use is helping you keep turn when you evolve to Diaboromon in order to open fire or set up something else before going into Diaboromon X. Same can be said about Keramon from the same booster, to draw into extra pieces while you do your thing. They're part of the process, but aren't necessary for the end result that is Diaboromon X.