Segwit allow cross blockchain atomic swaps, so trading without trusting your coins to exchange possible.  SegWit allow off chain transactions, so private transactions without coinmixers possible. SegWit allow instant transactions and allow more transactions per second. No matter how good or bad today implementation is, SegWit is a step in the right way. Network should progress,  anonymity matters, big tps and instant transactions is a must. Once litecoin adopts segwit all shitcoins become obsolete, so no wonder miners trying to derail voting and spread FUD here and there.