According to Inbox by Gmail G+ page, a recent update to the Inbox on Android app introduced two new widgets – one for setting reminders and another for composing emails.
The widgets are indeed on my phone after a recent update (at least I think that’s when they showed up) and I could see them coming in handy. For one, both the reminder and compose widgets can be dragged into a folder or in the app dock, just like an app icon. With that functionality, you don’t have to just set them on your home screen. They are still added as if they were widgets, but again, they really just function like an app shortcut.
With each on a home screen, you get to setup which Google account they attach reminders to or compose emails from, assuming you have more than one Google account. Once that has been set, a simple tap launches a compose window or new reminder prompt.
Check ’em out.