Definitely a smart move, as long as the weather is not an issue, as far as driving.
But, always a non stop, if possible. I look at the one way and roundtrip fares.
With EZ Air I haven’t seen much difference for one way or round trip on the International fares.
So, I agree it is better on a true b2b to book them as two one ways. Also, gives you a chance to reprice each one individually, if one goes down.
Domestically, I haven’t found EZAir a bargain, whether OW or RT. I usually book these directly with the airline and/or use my miles. There is usually a little bit better price on the roundtrip.
YMMV