Samuel Axon spoke to developers and marketing, developer relations, and engineering representatives from Apple in a story for Ars Technica about Catalyst, Apple's project for bringing iPad apps to the Mac.
Prior to WWDC, Apple gave a handful of companies access to Catalyst. Axon spoke to three of them about their experiences so far. Nolan O'Brian of Twitter, which discontinued its Mac app in 2016, had this to say about the experience:
"What Project Catalyst specifically offers is the ability to use our existing codebase, meaning that we don't have to maintain separate code or a separate team to support Twitter for Mac," he went on to say.
O'Brien said it was relatively easy to get going with the new app: "The surprising thing that got us excited about Project Catalyst was how much of our existing iOS codebase was able to just work."
TripIt and Gameloft had similar experiences bringing their apps to the Mac.
Addressing the concern that Catalyst means the end of powerful AppKit-based apps on the Mac, Shaan Pruden, Apple's senior director of partner management and developer relations, explained that there's a place for ground-up AppKit apps as well as Catalyst apps:
"Good developers will know their audience and their users and what they're going to want," she said. "This just opens the door for lots of people to consider coming that wouldn't have even thought about it before. And I think that's more the target for this particular technology as opposed to someone who has a very complicated, big, heavy-lifting kind of creative app."
Todd Benjamin, Apple's senior director of marketing for macOS, elaborated saying that he:
...believes there are fundamentally multiple types of apps, and they're not mutually exclusive with one another on a platform. And this is key to understanding Apple's approach, here. He said:
I think apps on the Mac have always been these large and complex and highly capable apps that are very broad. And I think apps on iOS by nature are a little bit more focused. They're highly designed. They're very much considered in what they do and how they do it. And I think that's changed how people look at apps, right?
The full story, which is full of detailed developer and Apple insights about Catalyst, is worth a read especially since it demonstrates just how nuanced the issues surrounding Catalyst are.