This provides an interesting balancing mechanic.
At low levels, where money (and magic items) are rarer, potions are very powerful commodities. Even fighters will get more bang for their buck with these, and as minor actions they add a terrific amount of healing.
At higher levels, the potions are still useful, because being minor actions they don't stop the hero from doing his thing. On the other hand, because they consume healing surges, high level characters aren't tempted to stockpile hoards of them.
Basically its a balance between 1 resource (cost) and another (surges).
I think its a nice way to do it.