I vote yes. Why? Well let's explore that...
Casual sex is a way to both be open, have honesty and remember your boundaries when you are starting your relationship. Yes it is a relationship; it's a casual sex one! You agree on certain things like not getting emotionally involved, not feeling the need to do sexual things if you don't want to for the sake of them, having more control over your sexual needs because you are not looking at the fear that may hold you back when you care for someone, and you have fun.
I am not saying do this all the time, or do it irresponsibly. Casual sex should be SAFE sex, should still be with someone you trust and know they are healthy in mind and body.
When you get to that point where you either feel like you want it to move into something more, or you want to move on to someone else, it has given you the freedom to decide in a way that has no strings attached.
We get into long-term relationships, we get into serious dating or even casual dating and there is so much pressure to perform! It doesn't work well that way. When you learn the freedom of being yourself in bed, being carefree and actually just going with the flow, the pressure is off and you actually have BETTER sex. There is freedom in it, you can say no and say yes to different and new things, you can see YOURSELF in a new way and explore your sensuality with someone who is doing the same.
I completely believe there is a good time and a bad time to have casual sex. You need to both be on the same page, it needs to be respectful and there can't be any expectations that it's going to become love. But...maybe it will grow into that, you never know.
WARNING: Casual sex is not for everyone, there are some that have emotional and spiritual connections as soon as they get to that point, so don't try it if you know this is you! The feelings and hurt that having those expectations can do to your soul are no bueno! Only go down that path if you can comfortably be CASUAL about it.
Taking a break from the heavy relationship stuff after a break up, feeling good after you have been single for awhile, or just being hot for someone are all good reasons to get it on. Perhaps it will teach you to take your carefree sexy self into a great relationship that is solid and the sex will feel effortless and amazing because you appreciate the person and the feeling of truly being in the moment.