The difference between Elk and traditional bridges is best illustrated in several examples. Say the user trades ETH for, let's say, "Anybridge" ETH (a.ETH). Then the bridge has to have enough a.ETH liquidity on the second chain the user is going to (i.e., exit liquidity) so that it can be transferred over. Then, the user has to convert a.ETH back to ETH, and hopefully that is also close in value due to different amounts of liquidity on different chains to ensure a fair exchange price, all the while paying lots of gas, and taking a hit if there is not enough liquidity for ETH on all chains. When traditional bridges introduce chains, more support is required for each additional chain, and not only do they need ETH liquidity, they need it paired with,. say a.ETH, to not take a big hit when selling. Plus with each new chain on a traditional bridge, the "two way bridge" requires a bridge to each new other chain. So if you have AVAX-ETH you have that bridge, but if you introduce BSC and FTM now you need AVAX-BSC, AVAX-ETH, BSC-ETH, AVAX-FTM, FTM-BSC, ETH-FTM, and it gets exponentially more difficult to maintain with each new chain, as it needs to have an individual bridge with every existing chain, as well as maintain enough exit liquidity on each.