It appears that currently “Task lists” in SP are not supported by PowerApps, it would be great if tasks would be supported so that project members can also manage their tasks remote (e.g. on the shopfloor).
I would love to see Tasks better integrated into PowerApps and Flow! In case anyone is looking for a potential workaround, I applied the Task Content Type to an out-of-the-box List. This allowed for some interaction with PowerApps & Flow.