In an attempt to answer the question seriously...
Straps and belt would not be considered fair play when comparing yourself to the results posted by other people under comments.
Functionality is a key concept of crossfit and belts and straps aren't very functional since it would be a rare occasion in real life where you had the chance to attach yourself to an object and reinforce your spine before lifting.
Also in using straps and a belt you lose out on two significant training benefits, training your grip and your back. Remember crossfit is GPP!
If you were doing deadlift as a SPP activity you might have a case for using straps if you were doing some high volume training and your grip gave out first or if you wanted to save your grip for another activity.
In the recently posted video of Pyros Dimas doing some amazing olympic lifts I noticed he was using straps for snatches, probably because it was close to a comp and he didn't want to fatigue his grip.
The belt is slightly more contentious. Really if you are doing deads for GPP then you want to avoid the belt because it teaches you a different method of core stabilisation (in my experience) which has little transfer to unbelted lifts.
If your back is tired and you need a belt then basically its time to stop lifting for the day.
Again for SPP the situation is different. If you compete in Powerlifting or strongman then the belt is part of your equipment and you'd need to learn how to use it to get the best out of your lifts on comp day.
My suggestion, do the workout as posted and record your results without a belt and straps. Then if you are keen you can go a little further and "practice" some deads with your gear.
Phew! long post, the snide one was much easier to write :wink: