Opera did it, too, and Vivaldi is a spiritual successor to Opera.
I switched to Vivaldi on Android because I didn't want to use Chrome, but Firefox on Android was doing two things that annoyed me: Reloading tabs when I navigate back to them after a long time ( which is a delay at best or loses the page state at worst) and as of six months ago, the screen would stutter when scrolling through pages like the New York Times.
Anyway, I tried Vivaldi mobile and liked it, then decided I might like the sync features between desktop and mobile, so I now use it on desktop.
And then I decided to try their mail client, which "just works" for me and my light usage. I already have the browser up all the time, so I hit F4 and check my mail.
Mail and Calendar apps are mostly used from the browser now anwyay.
Storing food and transforming food are not the same activity.
However, "trivection" ovens that use 3 kinds of eat and also microwave or toast are increasingly popular, because people very much like one thing that does several related things. (EDIT: Same story as the water + ice you agreed with below.)
"Get my stuff that's online" or "do things online" is one of those same-headspace things large percentages of boomers grew up doing in one place (AOL, then Mozilla suite, Opera, etc.), and "portals" perpetuated today by Google and Microsoft except as web apps in browsers (Edge, Chrome) trying to be the portal wrapping the web apps, which the same people tend to hate.
So Vivaldi gives the "one place" that works "one way" but doesn't feel like a weird web app you accidentally close a tab and lose everything.