I think the function of cross-chain and cross-asset exchange and multi-asset trading will be very useful
Indeed, it is. The idea is to provide freedom to users. Hence the "borderless trading" phrase. Switching form bitcoin to Apple stocks, to tokenized assets to fist in just few clicks open a lot of possibilities.
From a technical point of view this interoperability between assets is done through the network of liquidity pools and escrow type function. A use case is described in the whitepaper.