I like that it allows me to create tasks for my colleagues in one place so they don't have to search through emails or other communication channels for reminders of what is due next week.
It's also helpful when you're working remotely because everything can be saved as an attachment rather than having to type out each message over again if someone wants more details about something we've already discussed. The interface could use some work but there are plenty of third party apps which offer similar functionality (such as Asana) with better features/integrations. We were using Trello before but found its capabilities limited compared to others such as Google Drive and Dropbox Paper - this has solved our problems!