The problem I have with Bundle of Balloons is the monumental amount of work it takes to get them.
First, you need what is it again, 4 balloons? Have fun fishing for hours in the sky lakes.
Then you need 1 of each bottle, again, have fun doing a lot of fishing and scouring the world for the different bottles. If no Pyramid, have fun fishing some more or making a bunch of worlds praying that you A). Get a Pyramid, and B). Get one that has a Sandstorm in a Bottle.
By the time you finally do all of that, I would have just used wings, just 1 bottle+balloon and been in hardmode with real wings.
I see the Bundle of Balloons being a collector thing, something to make just to say you made it because the sheer amount of work that one has to put into it is nowhere near proportional to the actual reward you get out of it.
As for Potions, eh.
Sure that works all good and nice... until a potion runs out at just the wrong time because you got distracted or somesuch, and you scramble for the B key only to forgot that you had other buff potions on you and you end up wasting a bunch of potions you didn't really mean to use lol. Buff potions are OK for things that won't kill you if they run out at the wrong time, but I wouldn't feel comfortable using them for something like that.
That and you know, having to keep making them and having to keep using them to keep the buff up. I'd rather have something that's always there, and always active when it comes to something basic like movement.