Gp has been really underrated since his nerfs, his 'q' adds gold for dealing the killing blow, with mana return and slight mana regen you can safely farm with q under turret regardless of lane opponent nearly.
Let the enemy take the first wave of cs then freeze it till you want to buy. GG have cake
(The exceptions being champs with exceddingly long range, or 3 man ganks(or ganks with globals), but if someone does lane kog, xerath or someone with such long range against you, you can basically walk over them with two 'q' anyways.)