Well you are right. So don't invest in UNO. But keep in mind the same exact argument was made about Bitcoin, 9999 bitcoins wasn't even worth a pizza pie.
UNO is bitcoin elite, under 4 coins/day inflation, less in the future, attached to the bitcoin hash power (so secure if bitcoin is secure), and can utilize any code developments done by the btc core devs, cuz UNO is bitcoin but elite/rare, and fair.
In fact UNO is one of a few "actual" up and running and trading of these much discussed "bitcoin side chains". It is time tested and proven. But it is also a gamble, not a sure thing. So wait until UNO trades @ 1.95 btc, because @ 0.00333ish it is not a sure thing.
I don't think an investment is the same as a "store of value". One may invest almost any amount in the hope of a return, but for something to be a practical store of value it requires a reasonable market cap.
I'd be delighted for UNO to trade at B1.95 but I'm not holding my breath, sadly.
Finally UNO is not a "side chain" of BTC, at least not in the terms set out in the sidechain white paper. Being merge-mined does not a sidechain make.