What I meant was, is there a reason to keep it low beyond "bigger isn't necessary"? Like a performance reason for instance, or an address is like a URL so shorter is easier to remember, or something like that.

The reason I ask is if there's a good reason that a bigger address space would be worse in some way, then "bigger isn't necessary" might be a decent argument, but if there's no good reason not to make it bigger, then it's not such a good argument.

While planet names would get harder to remember if they were longer (48 bits and six syllables instead of 32 bits and four syllables), the main reason they want the address space to be somewhat scarce is to make spam economically infeasible.