The extra long frame sliders can be 50 50 as to whether they are effective or not. A low speed front end tuck, where the bike stays on the track, they can work quite nicely, but often when they transition over a curb, they can tend to catch and can start the bike tumbling doing much more damage.
This.
I used to be an on-track instructor for one of the largest track day providers in California. I've done over 100 track days, crashed a few times myself, and helped pull a
lot of crashed bikes out of the dirt. If you crash and your bike slides to a stop before leaving the pavement, then frame sliders are brilliant! If your bike slides off the tarmac into the dirt, which almost always happens, the frame sliders are a liability. They'll cause the bike to tumble, or get ripped out of the frame completely, or bend something that shouldn't be bent.
For all of these reasons, I no longer use frame sliders on any of my bikes and haven't used them for years. If I were taking a Multistrada to the track regularly I'd want to protect vulnerable portions of the engine. The water pump and radiator look pretty vulnerable to me. The horizontal cylinder would also worry me. I'd be tempted to install the Ducati Performance engine guards, but I wouldn't expect them (or anything else) to save the bodywork. It's a shame that Barkbusters couldn't figure out how to protect the stock hand guards and levers.