Without a doubt, the inclusion of Dash in many markets. An instant or private delivery is useless if no one or almost no one accepts it.
Working on acceptance will bring the rest.
Imagine, for example, that I want to buy some sneakers and I have IOTA or BTC or ETH in my wallet, and I need to make a quick payment with hardly any fees. But the merchant has not heard of Dash, but of BTC and says that he only accepts BTC... Dash's speed is useless.
Work must be done to publicize instant, decentralized and secure delivery. With that alone, Dash should break through any barriers and be above many coins with hardly any real use.
I love that Dash continued with the original promise of Bitcoin. Peer to peer digital cash. Many of the problems I could see in Bitcoin from the beginning have been improved, and Dash continues to innovate.
Dash's combination of being fast, easy. widely accepted, and secure make it very attractive today. The improved ease of use that will come with Usernames and the dapps that will come soon, remind me that we are still on the ground floor with this transformative technology.