Very relevant since, as far as I know, we've been stuck many years without a free and decent multiplatform application that could handle multiple email accounts. I've been using Mailbird (paid) so far, and I'm considering to switch to this now that I've seen this announcement and tried the client. Vivaldi is my favorite browser so far because it's the closest modern alternative to the good old Opera, back when it was a feature-rich internet suite, with integrated email and torrent clients and whatnot. For the privacy concerned, I'm fairly confident that, when paired with the uBlock Origin extension, it does a better job at that than (((Brave))), which has done a lot of false advertising in the past. A common complaint is that Vivaldi is not open source, which is not entirely true since the source code has been publicly available from the start, just not under a open source license: https://help.vivaldi.com/desktop/privacy/is-vivaldi-open-source/