Email is only an asset in so far as people actually open and read those emails. I tend to stay away fro subscribing to things via email as I view it more as a work tool. I find I rarely read newsletters via email. I’d much rather read short tidbits in email and reply to them if necessary.
It’s a different experience opening my feed reader (or as I prefer, my social readers like Indigenous for Android, Monocle, or Together) where my intention is to then read and potentially interact with things in a dramatically different fashion. There I’m not visiting most of my subscriptions with a “work” mindset the way I approach my email. I even have different folders of feeds which I think about, read, and interact with in dramatically different ways.
Some of it comes down to what permissions you as a user and consumer want to get out of those tools. Some of it comes down to what expectations you as a producer also have in how people are going to interact with and consume your content.
In Roberto Blake’s framing, the content he’s creating is for his work/business, so perhaps email delivery is the most effective venue?
At the end of the day, the specific design of the tools and the ways users choose to use them will create very different outcomes for everyone.