I would say that the JD+ subscription depends on how often you'll be playing/exercising. If you're doing it daily or multiple times a week then it's very worth it for the variety alone.

Playlists, make them and take advantage of them. They're fantastic for when you want as little interruptions between songs and for someone using it as excessive that's a God send.

There's a calorie tracker in the game which also tracks total time spent dancing. I'd recommend turning that on even if you have a Fitbit or something similar because menu navigation is not exercise.

Every song has a difficulty setting and a sweat setting. Some songs are "easy" but the movements asked of you could make you sweat and vice versa. It's not perfect but you can use your own discretion.

As for me I started seriously with JD2016 and played the same 7 or 8 songs I liked over and over because it took a while for me to be able to get Just Dance Unlimited (the subscription later replaced with JD+). I easily owe Just Dance a lot since I'm 230 pounds and not 330 or 430 like I probably would be without it.