1 this is a forum full of people who actually understand about sound
its like mechanics saying its an easy fix. it could be easy for a mechanic

2 matching speakers front to back makes it easier to tune the system as a whole because all 4 speakers have exactly same output curve.

3 without a good dsp it is harder to make it sound good overall if the pairs of speakers have different frequency response curve and sensitivity and power handling.

now if you of course involve DSP and proper crossovers etc of course the brand and model of speakers and tweeters becomes irrelevant because you shifted the sound control to your DSP.