In Short:
I had very good experiences so far with Google Domains, now why don't they offer SSL certs?
TL;DR:
I use Google Domains to buy/transfer domains recently for friends and small clients which only need a basic website, and I have very good experiences with Google Domains.
It has very clean UI, very simple and easy to use, straightforward, no hassle, no bullshit.
Flat rate at $12 for .com domain per year, with Private registry for free.
($20 for .me domain, and might have limited TLD or a bit higher rate comparing to others, but still cheap)
No COUPON whatsoever, just flat rate for every year.
(I'm laughing at GoDaddy which trick you get x% discount on the first year and get much higher rate next year. And you keep getting emails about expiring domains/and discount codes if you wait till the last day.)
No upsale. It offers partners site like wix.com, weebly.com, squarespace.com if you want to host website there. Or you can use Google App engine or any VPS to host website.
Another benefit is to easily integrate the Gmail for Business/Google Apps for Work.
So, now, why don't offer SSL certificates?
They have our Gmail, Google+, and they have very good ideas about who we are and can easily verify our identifies, to issue a Class-2 or wild char Certs. Don't they?
I used to use DynDNS (of course I've been using them since way-back-when in the modem days for dynamically updated sub-domain services), I got away from them just recently.. way too pricey for my needs, especially considering I needed to do multiple domains.
Google Apps for Work/GMail are both easy to integrate regardless of whos holding on to your records or hosting your name server, I don't think that should ever be an issue.
How's the "Google App engine"? I use Cloud9, and its unbearably slow -- but who knows what they pay for and how much they overload their machines with containers.