Why does super corrupt vergil have his moveset from dmc1 in dt?

[Verdugo]

I finally beat dmd with vergil and when i entered bloody palace with super corrupt vergil costume i noticed he transformed into Nelo Angelo from dmc1, but why does he also have his moveset from dmc1? Super legendary dark knight sparda doesn't have unique moves like vergil has and why is that?

[Director Bison]

If you want to get into specifics, Dante's LDK Sparda costume was in DMC1, but aside from starting the game with Yamato "which is an Alastor Reskin in DMC1" and DT. Sparda Dante plays the same as Regular Dante, so DMC3 LDK Dante's gameplay doesn't change Dante's playstyle is more or less still the same in DMC3 as it is in DMC1 anyway.

Now Vergil it's a different story since Corrupt Vergil is the state he is in after fighting Mundus, that is essentially what Nelo Angelo looks like without the Armor, so the DT Form is the full on Nelo Angelo movelist.

But really it's just because it's cool and they had the assets. DMC2 has a similar bonus in that you can unlock a DMC1 Dante Costume for beating DMD mode as Dante and it reuses Voice lines, and Sound effects, and Music from DMC1. Also unlocking Trish by beating Hard mode as Dante has it so her move list is a bunch of DMC1 Dante's moves.