I am a bit confused about this differential base-emitter resistance.

I has been said that r_pi doesn't have much influence on small signal input impedance, when CE with emitter degeneration is used. Well, I doubt this claim.

Why? Emitter resistor will be most probably bypassed by capacitor, so emitter can't really have much influence on small signal input impedance.

Can someone please explains why or when should r_pi be neglected in small signal input resistance calculus for CE with emitter degeneration?

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/q6KOQ.jpg