Sions Q, despite immediate appearances, isnt a Damage or CC ability despite appearing as such. it's a zoning ability. the point of it is to create an explicit threat and punish missteps. if you've played any orianna its actually pretty similar in concept to threatening enemies with using the ball to ult, rather than as a poke tool or to try and land game winning cc. you need to set up situations to use it and explicitly challenge enemies to play and worry around it. use it to force enemies into losing cs, or to cut off an escape route.

That all sounds like a "win more" scenario to me. When mobile champions with 3+ dashes can instantly get in and out of your range at any time, creating a small zone usually isn't that much of an obstacle, they have the tools and mobility to run or jump around it. And again, can't any other tank to the same but strictly better?