[anyfoo]

It's not much of a problem for (v4) IPs, because they almost always consist of 4 numbers separated by a dot, making them immediately distinguishable from decimal numbers. If two-component IPs were common (they are sometimes seen in CIDR notation, but not often), the dot would have been an unfortunate separator choice as well.

For versions with only two components, I would argue that the dot can be confusing already.

Why use a separator that has the potential of confusion when there are several other choices with less potential?