No strings attached
The number one reason to go with friends with benefits is that there are no strings attached. Most adults like the ability to see the person when they want, but they want someone who often enjoys intimate time. Yes, women want this too. No strings attached also means that relationships are easier to manage. No complicated planning, no need to worry about anniversary, etc. Everyone wants to simplify their lives and eliminate stress. There is absolutely no pressure to be with the friends with benefits.
Have a fwb dating means you don't have be experience any drama or stress. Even if you do, you can always find a new fwb dating. There are as many affair dating partners as you want. You are not limited to having only one friend at a time. You can hookup with with as many nsa finders as you like with casual hookup sites.
No promise to be with someone
Not limiting your number of partners means you need safety. When you are in a friends with benefits, you should often use protection. You can have a lot of nsa fun when dating, but most of the time you need to do more than just intimacy. Dating, spending time together, cleaning and more. But all these are not with FWB relationship.
When you are in fwb dating, do nothing but intimacy, and you can have fun when you want. In fact, when you are together, having intimacy should be almost the only thing. Friends with benefits should not do other things. In most relationships, asking the FWB to do more is considered taboo. Everyone is looking at others, but when you are in love, that is not allowed. If your adult friend catches you doing this, you will be in trouble.
In very rare cases, you are outside with your FWB, and there is no reason why you can't check someone, because there is no attachment to each other except for intimacy. There are many potential adult friend finders watching and you can watch any one when you are in a friends with benefits. It's easier to talk about your desires. When you date someone, you are worried that it will make the other person uncomfortable or annoying.
A good friends with benefits is both parties are comfortable with each other. Both of you are friends and affair dating partners. You can be intimacy and good friends. FWB dating means you two meet each others' desire, either for adult affair dating, or for good friendship.