I think your not wrong, but Monero has a killer feature, privacy.
I think at the end of the day the great UX doesn't necessarily need to come from the currency but can come from clever apps. When you think about making a credit card payment, its horrendously complicated what goes on in the background but the user never needs to know. It all just works.
My Two cents on the viable currencies:
Bitcoin has volume and relative stability. Thats a killer feature for some things, it could form the backbone of some international clearing system or long term store of value. It doesnt necessarily need speed to work for those just stability and security.
Dash/Monero have speed and and are all viable as payment currencies for everyday use. Dash seems to be pulling ahead but lacks the privacy of Monero which could prove more important. It will be interesting to see how these currencies scale and if this uncovers any issues.
Steem is super fast, can handle high volumes and has been built from the ground up. The complicated 3 states of Steem is quite ingenious, I am still trying to get my head around it but your right its difficult to get across to people. And with regards Steem and its future a lot depends on how rewards end up being distributed, what the whales do, future hard forks etc .... there are so many variables with Steem but its promising. I would like to see a nice slick wallet app for it soon. That would be cool.
UX can come from clever apps, but someone has got to make the apps first. Bitcoin has been around for years, and nobody has really improved its UX, so I have to wonder what would make Monero different. No cryptocurrency really has it down yet, but from the information available, Dash is going to be the first.
Bitcoin has stability for now, but if that's its feature, then any currency which overtakes its market cap is going to displace it. It doesn't need to be fast to work for a clearing house, but a currency which is fast is obviously superior.
Dash does have privacy though. You can make transactions private with Dash, and you can make public ones too.