I love Tapwater and there are many possible uses for it. It's an effective tool to manage ideas, documents and conversations related to the project in one place. I love that I can talk to my client and just add everything there under a specific project. much like a brain dump. I can't think of any use for this right now for project or task management. Tags can only be added after saving the form and not in the same screen with the wysiwyg editor.
I have a feeling that it hasn't discovered what its purpose is yet. I'd say it's basically a brain dump for projects but pretty weak in areas where you can capture ideas and conversations
Integrations to Slack where ideas and conversations takes place would be cool. Being able to capture ideas in the middle of a conversation would be really helpful. It's a unique app on its own and still discovering itself.
Given its different approach to project management, it might take a bit before you get the best out of it (especially if you come from Basecamp et similia). Once you get how it works, it is just natural adding milestone/things to remember about each project.