Marzipan apps are ugly ducklings. As soon as you use them, you can just know these are not at one with the system. You detect that there’s a translation layer of some kind at work here, just like when you use Slack on the Mac you instinctively feel that it’s a web app in a thin wrapper. The underlying implementation is exposed to the user with a bevy of performance sluggishness, UI quirks and non-standard behaviours. That’s bad.
Awhile ago I wrote about Marzipan and included a crowdsourced list of “what makes a Mac app a Mac app.” It was a pretty comprehensive list, yet lacking in minor details. I knew there had to be a bunch of nitpicky visual annoyances and UI oddities, and Benjamin covers those really well in his post. I feel like I have a much better understanding now of what needs to happen for Marzipan apps to feel native on the Mac.