It means that we get to try to focus on making one experience strong. That said, ultimately the user is providing data which is independent of the look, so evolving a desktop variant is totally doable.
We're (currently) keen to not necessarily run towards traditional responsive design. The reason being that you have a lot of design consequences / unintentional visual limitations - it's one of the reasons a lot of websites kind of look the same, especially from website builders and tools (they go heavy on block layouts to make it easy to deal with responsive).
All that said, it's iteration 1, and our launch is really a 'beta' launch more than anything.
Would you mind elaborating on what you think those limitations are?
I feel like it’s easy to say ‘nah we don’t do responsive’ instead of figuring out a way do just do it. I can’t come up with a single example that I couldn’t translate from mobile to desktop in some way.
As the foundation of this app is the idea that a user can just switch layout/visuals, it needs a lot of visual looks to switch between. Doing a lot of those, and having the responsiveness, and then iterating on app/data model features (which need updates to those designs) is quite a drain on speed.
All that said, since you asked for a single _actual_ example, I have one which I think is quite problematic (though could be addressed in some way, just not easily). We've kicked around the idea of letting users place stickers over the top of their design in order to customise them (a little like Instagram Stories), it's not obvious how to migrate a user input visual through a responsive set of designs without a lot of trouble (the most obvious solution being to guess and then let the user tweak at different responsive breaks).
Hopefully that convinces you that it wasn't just a throwaway 'nah we don't do responsive' :) I'm sure we could do better than where we currently are, and it is an iteration one release!
Disclosure: I wrote a lot of the code to power the wrap frontend, but I'm no longer involved with any of it.