Candles of Invocation cost 8,400gp, CL 17
Scrolls of planer binding cost 1,650gp, CL 11
- +Scroll of magic circle against evil which costs 375gp, CL5
+Scroll of dimensional anchor which costs 700gp, CL7
Granting 3 wishes is something noble dijinn and efreeti can just do as a standard action (SLA grant 3 wishes 1/day). so in core only games you don't have to negotiate or pay them when you gate them for wishes, and you don't need to pay to get creatures to agree to give you wishes either when ensnared in a planer binding spell; OR like me you play a Tome game so you always must negotiate payment for wishes.
In fact the only thing that's different, besides the price, is that planer binding allows a save to be resist being trapped, which is what you expect because it is both lower level and cheaper to purchase than anything with gate, and you have to have a specific type of candle of invocation (either chaotic good or chaotic evil) to get wishes at all.