I use Paper and have to say I quite like it - I started using it at my current job where it seemed common and hadn’t heard of it before. The main thing I like it for is quickly putting together group TODOs - you can create checkboxes with [] and can tag people’s names to items and add deadlines. That combined with some indentation is exactly the level of structure I like to organize such things. I’m surprised to find out here that it seems so unpopular.
My startup also uses Paper (and we love/have loved it) but are migrating more and more to Confluence recently. I still use Paper for quick brainstorming/organizing for smaller groups and projects, though. The collaborative editing and always-on edit mode make it great for documents in rapid flux, whereas Confluence is better for long-lived strategy and documentation related items.
