Hilton already has a brand that represents a grab-bag of weirdly disparate none-of-the-above properties from quirky to dowdy to luxurious that they don't know what to do with. It's Doubletree.
Some Conrads are better than hilton, some hiltons are better than conrad, heck, even some doubletree are better than hiltons. So yeah, hilton will probably market them as "upmarket" but it will be down to individual property.
With no discernible consistent standards defining Conrads and separating them from Hiltons, this just adds another instant identity crisis to the Hilton mix. It doesn't make any sense, especially as Curio will include purpose-built new properties (e.g. Portland) that might as well be a Conrad, etc.
As far as I'm concerned, the only Hilton brand that has true focus is HGI. All the others are all over the lot, from grim to lovely. Curio is just another confusion point.