While everyone is certainly entitled to their own opinions, FWIW, here's mine.
Although the original question does provoke different thoughts, I don't think it is relevant to the actual sound a speaker will produce. It is possible for a speaker with a somewhat limited frequency extension to have an unpleasant treble, and one with much more extension to sound very pleasing or vise versa. It is much more important to consider synergy of the system's components and cables with the speakers.
Having experience with various models of JMR speakers, I found that two, having the same specification for treble response sounded quite different in regard to "air or sparkle" with exactly the same components and cables. Trying different speaker cables proved that one speaker seemed to be affected more than the other, and could sound quite good with the right cable.
When looking at a speaker's specifications, I think sensitivity and impedance characteristics are much more important, so that you match a suitable amp. This assures peak performance, then use other components and cables for good synergy.
I'm looking for ways to reasonably narrow the field.
Of course, taken "with a grain of salt", reading multiple consistent reviews, and seeing the same comments on this forum about a speaker makes more sense than looking at a frequency specification, IMHO.