Its doable, but its not easy and requires more than just being in and enjoy a relationship. It's expensive.
being in a casual long distance relationship is just silly and a waste of time. Also some people aren't and some people are built for it.
If you don't know how to be alone, not have sex all the time or enjoy time with just yourself you might not want to do it.
Its almost like being married but without the intimacy of marriage. It requires a lot of trust and knowing that the person is dedicated to you.
Basically its hard, but anything worth having is hard.
Relationship these day's are way to casual anyway. In a twist of things LD might be the ultimate test of weather you and your partner are ready for the long term.
If you don't have a end goal like moving together and or marriage its pretty pointless and will lead to headache and heartache.