The main drawback is that RDEs need substantially stronger structure to smooth out the forces. It's still worth it, the force of the detonation (it's not separate explosions, it's a single continuous detonation front moving in a circular channel) is small enough to be containable.

There have been tests with multiple detonation fronts, but controlling them is much harder. It's very hard to have them go around the channel at exactly the same speed, so their positions relative to each other remain fixed.