I had a pair of Alons that had the tweeter and midrange mount on top of the woofer, which was inside of a box. You couldn't tell because it had an interesting angled grill cover so you couldn't see there was no box holding those drivers. They had an amazingly big sweet spot and overall they were very easy to listen to. Kept them for 25 years.
Just last year replaced them with a pair of KEF R500s that are more detailed, dynamic and have WAY more bass, tighter, deeper. Not quite as big a sweet spot, but still very good in that regard.
I don't think you should generalize about the speaker type because each one has a different design. By and large though, total OBs can benefit strongly form subwoofers, which makes the whole system into a bigger more complicated deal.
Just last year replaced them with a pair of KEF R500s that are more detailed, dynamic and have WAY more bass, tighter, deeper. Not quite as big a sweet spot, but still very good in that regard.
I don't think you should generalize about the speaker type because each one has a different design. By and large though, total OBs can benefit strongly form subwoofers, which makes the whole system into a bigger more complicated deal.