First of all UNV has a 0.01 BTC value to have a point of reference of value in the crypto community.
Then it will have also a value in $,€, £, Yuan, Yen  as every worthed crypto.

So it will be tradable with fiat currencies also, in this order UNV doesn’t need to absorb whole BTC amount.

Remember the main goal of UNV is to absorb whole world mass monetary and not just the 21 M of BTC.