We believe a token can add value to a network, if it incentivizes participants to do something useful for the network itself. For instance, requiring fee payment with a specific token adds an additional entry barrier for participants, which we don't consider to be very useful. XUC instead is designed to incentivize market makers to provide the most crucial element on OpenDEX: liquidity. The OpenDEX network and xud software are entirely token-free and do not require holding or using any particular token.
Market Makers which decide to hold XUC, receive a XUC token subsidy for providing liquidity on the OpenDEX network in its early stages. This incentivizes market makers to run xud nodes and lock capital to provide liquidity on the network, even when trading activity is still low. This is an essential incentive that helps to bootstrap the supply side of the OpenDEX market place. It can be somewhat compared to the bitcoin block subsidy which rewards miners for securing the network, when transaction fees are not high enough to amortize costs yet. This is, once more similar to bitcoin, how XUC is distributed: to the partipants that help the system to grow the most. In future, XUC will unlock optional services improving trading reliability.
We believe a well-designed incentive system is vital to the success of a market place that faces the typical chicken egg problem of growing supply and demand at the same time. XUC helps the supply side to grow first by subsidizing market makers.