Good on you for putting something together, but I think your original complaint about Google not putting something similar in GMail is way off.
Email is an inherently asynchronous medium, it's up to you how frequently you check it. Having notifications and the like in your browser, on your phone, elsewhere, they're all your choice.
Fair point. I like hitting the do not disturb button along with my phone's do not disturb ... it has a mental effect on the mind ... and allows me to focus more clearly on other things. The scheduled quiet hours are also cool.