"Direct radiator" speakers still generate a lot of off-axis energy and therefore a lot of reflections.
At most normal listening distances in most rooms, most of the sound that reaches your ears is reflected sound. And most of that reflected sound started out as off-axis energy. What we perceive is a weighted average of the direct + reflected sound, which implies that what a speaker is doing off-axis (including around back!) matters.
A bipole or dipole speaker produces additional spectrally-correct reverberant energy. With proper set-up (dipole and bipole speakers should be out in the room several feet), this results in a warm, relaxing, rich timbre. They also do a good job of conveying a sense of immersion and of disappearing as the apparent sound source.
I’m a dealer for dipole speakers and used to build bipolar speakers. What I do now shares some common ground with bipolars, and I still think very highly of the format.
Duke