There's no thing like there are only some states if matter,

Its just how the matter behaves.

In our human world we can observe 3 states of matter.

Bose einstein condensate is the group of bosons at 0 temperature of universe.

So we can only observe it with special observation things.

For 0 temperature of universe the group of bosons has to be cooled in a very special apparatus.

So we can't observe it directly or even touch it.

Because if we even want touch it our hand will also get into different state of matter even close to it, and our nerves and every sensory biological things will stop working.