Like most things it is a trade off. Lower sensitivity speakers are generally more linear, have greater bandwidth and are generally more accurate (less distortion). It is easy to make a high power amplifier that is extremely accurate (just expensive) it is also easy to make a giant speaker box to get great accurate low end efficiency (again only expensive to build and ship). It is extremely hard to make a light weight diaphragm or cone with a small drive motor and drive it with next to no power and still get anything approaching high fidelity. Just think about it - all of the friction, resonances and other issues of the mechanical cone are relatively much larger compared to the relatively weak but highly accurate drive electrical signal in a high efficiency design.
High end Studios (million $ facilities) have gone gone away from horns for this reason - lower efficiency speakers tend be more accurate and horns tend to have a shouty character due to directivity and non-linear air compression at higher SPL.
High end Studios (million $ facilities) have gone gone away from horns for this reason - lower efficiency speakers tend be more accurate and horns tend to have a shouty character due to directivity and non-linear air compression at higher SPL.