No exercise you get is "for nothing". If you raised your heart rate, then you did something and burned calories.
For some reason people have this mindset that if they're not in a panting, falling down, sweaty heap at the end of a bout of exercise, that it's "for nothing"!
Soreness is normal since you're probably using muscles you haven't used in a long time ... and that also is a good sign.
And besides, it's nice to mix it up every once in a while!