I've never really commuted with a trailer, nor do I think I would want to. Curb hopping is a bit more challenging with a trailer, plus its width becomes a concern in a more congested area. Parking could be an issue too.

A cargo bike's main drawback is the additional effort it takes to get from point A to point B. Whether that is a legit concern is completely dependent on your commute and your ability. It's not a big deal to me.