Ease of finding an exoplanet, among other things, increases with proximity.
A close and attentive reader of my original comment might possibly note that my argument wasn't for Gliese but against a. centauri. The salient point being that you'll need to schedule and budget for markedly more than 4.6 light years.
Closer exoplanets aren't necessarily easier to spot, we've spotted those around Gliese 581 because they have a nice short period of a few days.