|Your links to the anti-mush resistance allow you to understand and decode rebel transmissions much quicker than any other radio expert.
The same effect can be acquired by contacting Kivanç via the Xyloph DB, though, and the bonuses stack (+200% efficiency on decoding). While beneficial, this means that after finding Kivanç, the Rebel skill is much less important, as it then only saves 1-2 additional every time.
Also, an experienced Paola is likely to skip less worthwhile bases in favour of doing other things (like finding that bonus), in which case the skill may only be used on around 4 bases, for a mere 4-8 saved all game.
So while useful, a level 5 Paola definitely has more important skills at her disposal.