I am a little disappointed that Vivaldi did not do so well in this test. What do you think? Is there a way to improve Vivaldi in these areas? Is it necessary? Should privacy-conscious people use another browser?
It depends on what you want from your browser. It’s not the best in privacy and it’s not the best in security. It’s also slower than most other browsers due to the all the UI stuff they add on top of Chromium.
You can harden it to some extent by installing uBlock Origin and Privacy Badger. But every extension makes you more fingerprintable.
But Vivaldi shines in productivity especially combined with vimium. Being able to tailor every single action to your preference can save a lot of time.
I would suggest using a variety of browsers based on your activity. I use Vivaldi as my main work browser, but when I visit new sites I’m more likely to open them in a different more hardened browser.