I'd bet a lot of money that doing voice work is a lot easier than being in a live action production. Not saying it's trivial, just potentially way more flexible, especially with how easy it is to splice different audio tracks together, which probably means fewer takes are required. And on top of that, there's fewer people that need to coordinate to record those takes (especially considering live action takes likely requires more audio engineering support because it isn't done in an audio recording studio).

It might be like a pilot deciding they are done flying commercial jets but don't mind flying a smaller jet from time to time.