If your talking about strumming patterns they are good to practice, now if your learning your first new song & you do your own strum and it sounds good go for it..
Strumming is very important! You can completely change the feel of a song just by playing a different strumming pattern with the same chords. And if you're playing something that repeats itself a lot, it's fun to mix up the strumming pattern to keep it interesting.
You can make up your own strumming patterns if you want. Whatever you feel fits the song best is fine. Still, it doesn't hurt to learn as many as you can.
There's a time for strumming, a time for picking, a time for singing and a time for pause. What was the name of that song? Oh yea, "Graduation Day". It ends with, you're the priest of your own temple.