Pioneer DJM-S7 questions

I’m looking forward to buying this mixer, but I would appreciate it if someone could share their experiences using software like DJAY. The mixer has built-in effects that I want to take advantage of, but I’m not sure how DJAY will handle them or how you’re supposed to switch from the built-in (analog) effects on the mixer to DJAY’s software effects.

I saw some videos of people using it with Serato, but I’m not sure if it would work the same way. Also, is this type of mixer intended to be used as an external mixer or an internal one, and what’s the main difference? Does using it as an external mixer cause any software limitations?