Lists
First things first: Vikunja can create lists. And yes, you can add tasks to a list. But it can do so much more (or at least, it will be able to do a lot more at some point).
Namespaces
A... what? A namespace is something like a group of lists. Every list is part of a particular namespace which you can then share or simply use as a method to keep track of multiple lists more easily.
Tasks
Tasks are not only simple tasks. You can let Vikunja remind you of tasks when they're due. Never miss an important deadline again!
Sharing
Ever wished you could just share that grocery list with your roomate instead of having to send dozens of texts on your way to the supermarket? With Vikunja, you can. Simply share a list or a namespace with all its lists to another user. Don't want your roommate to add new things to the grocery list and only do the shopping? You can also share a list with read-only access!
Planning a bigger thing? You can use teams to share a list or namespace with multiple people at a time!