PS: let me be more specific, cause this statement conflates two different meanings:
1. Assets bridged to CKB (like BTC, ETH, DOGE …)
xUDT is the chosen standard for assets who are gonna be bridged to Nervos L1
Let’s say that Core Team was to deliver betterUDT before Rosen Bridge mainnet deployment, I would personally be very happy to switch to betterUDT in Rosen Bridge. See: Pre-RFC Discussion: Activating the Nervos DAO Treasury - #12 by phroi
2. CKB Native Assets (like CKB, iCKB, SEAL …)
We don’t need to support only xUDT here, we could easily bridge from Nervos L1 to other chains future betterUDTassets or even sUDT ones.
For example, notice how sUDT is a references by type, but non-upgradable, cause the lock locking the sUDT binary is a zero lock: https://explorer.nervos.org/transaction/0xc7813f6a415144643970c2e88e0bb6ca6a8edc5dd7c1022746f628284a9936d5
By default sUDT assets are as much decentralized as xUDT ones