I use FreshRSS which is similar to tt-rss. I really think I should turn on email digests in it because I often find myself forgetting to check my reader some days and then it feels cumbersome to try and "catch-up" with the feeds.

I actually really like the idea of being able to convert newsletters into RSS feeds. I have a decent amount of newsletter I currently get and for a lot of them the only reason I have them in newsletter form is because they offered no RSS option. So if I wanted to stay up to date one of my only options was newsletters.