I don’t understand how utxo sharing works or even could work.

But I can tell you how to think about it. Any software trick that allows more people to transact per byte of block space is potentially critical to the survival of bitcoin.

Remember, bitcoin must evolve to spread cost of ongoing security to whichever users are currently transacting. Right now, hodlers are paying most of the cost of security by permitting debasement of their coins.

This is why every successful halving is worth a party. It means technology grew sufficient to spread security costs over enough users to keep the system running securely with half the debasement subsidy.

If bitcoin doesn’t get used more efficiently, this system won’t last much longer. Bitcoin has to incentivize new and clever ways to be used to keep it alive.