When tapping 'Watch Now', the overlay comes up, requiring one to again tap 'Watch Now'. Not sure of the reason for this, but how about when tapping the initial Watch Now, that the overlay comes up and the show starts playing?
I may be mistaken, but I believe this is due to the web browser itself blocking auto-playing of content. So, this isn't something Channels has control over, but rather Google, Mozilla, or whoever provides your web browser.
How do sites like CNN and others do auto play? If the issue is the overlay, than I'd vote to lose the overlay and load a new page, if it meant being to get auto play. For me, when I click that initial Watch Now my expectation is that the video will start playing.