Why is even mode rejection good?

Hi guys,

I am currently studying the advantages of differential feeding in antennas and i came across this in a paper:

However, an even mode excitation of the two ports will not
excite a radiating mode in the antenna, so the majority of even
mode power would be reflected back to the generators. Such
even mode rejection is an important advantage in the highly integrated
mixed signal applications in which we envisage this
type of feed being used.

Unfortunately it did not explain why even mode rejection is an important advantage. Anyone care to explain?

In even mode both the signals are in phase, we have two cases to consider
1) while transmitting.
Majority of even mode power would be reflected back to the generators. so its draw back and care must be such that the generated power will not be feed in even mode.
2) while receiving.
As we know that antenna is bi-directional, when it is not radiating even mode then it will also not receive even mode signals, this makes antenna as more rejection to even mode signals.
This is very useful topic in case of multiple antennas placed in a tightly packaged cellular phone.