If I remember correctly, the one on the right comes in a male, female. You can insert the male into the female, but BOTH are fully inclosed. Mostly, it dosnt make a difference when using these connectors. But every once in a while, like when you have to redo the magnetic pickup wires, its kinda neat to be able to insert them into one another. And, as a matter of fact, the connectors for the mag pickup, and the wire harnes ARE such connectors. The barrel is a tad longer then normal, and that makes it much easyer to get them apart, when you need to.
I do have the male counterpart for the one on the right. Nice if you need a disconnect on something. Never have seen the long barrels, that would make it a lot better for pulling them apart. Once replaced a connector with one like on the right and 2 weeks later the connector came loose again, replaced with one like on the left and that did it. Could have been a bad connector also.