Keeping SmartScreen enabled actually prompted me to disable several malware domains lists in uBlock Origin for being deprecated and/or redundant. Unfortunately, it's only for Microsoft browsers., so Vivaldi has a couple more phishing/malware filter lists in its uBO..
I'm relying more and more on uBO (and for Edge, SmartScreen) for better browser security--it's minimal in resource consumption and I see the effects when it counts. That's one reason why for me, SmartScreen is a must-have.
I use Firefox for most browsing, so I rely on the (new and improved) malware and phishing lists in uBO as well as the FF built-in "safe browsing" and system-wide Smart Screen. As appealing as I find the new Chrome Edge, I am too set in my ways with Firefox to switch at this time.