Focusmate is a great product centered around virtual co-working and work productivity, whereas Double will not be centered around co-working, but for everyday tasks (which can include co-working). As a result, we are designing the experience to be tailored towards the everyday experiences rather than a co-working product used for everyday task.
Essentially, we want to expand the scope of tasks you can double up to do together and provide a better UX for those diverse tasks.