Yes, it will allow you to use a higher frame delay setting. The main component is the CPU, but the GPU is relevant to MAME, and thus to GroovyMAME as well.
Plus you get the ability to play other games at 15kHz. Tons of new games can scale down - Tekken 7 for example. Not to mention Teknoparrot.
The 380x isn't likely to work with Atom15 however, so you have to account for that too.