I use Nylas but I recently had to move from a 2013 MBP to a 2008 MBP and it shows how unresponsive the UI is. I'd like to use something such as mutt but I find it very unfriendly.
There are serious privacy concerns[1] with spark though. One alternative to Polymail which is not often discussed is Canary Mail[2], which I've always found to be reliable and good looking.
Nylas has a keymaps.json (as well as the UI of course) which is a +1 in my book. Unfortunately other things missing from textual config, such as mail rules (filters).
So much for people saying "machines now are good enough for most basic uses and don't need upgrading anymore"... I guess Intel should be thankful for The Rise Of Electron Apps.
And modern software that behaves respectfully, I'd expect, especially if it's doing something that my 100Mhz Pentium w/ 64MB (with an M) of memory used to manage just fine (graphical email client). With the bonus that newer machines can run more such programs at once, and enjoy longer battery life.
I'm not sure what your point is. Nylas looks pretty cool, but is it doing so much more than other 10 year old email clients? Is it features or implementation choices that lead to relatively high resource usage?
