The bending shows it was likely put in upside down. Convex end goes down, concave goes up. The jet holder has a cup end to meet the convex and thinking both ends are different diameter, looks that way in the pic anyway. The bigger end would not go up in the smaller hole.
Can't imagine not using them as doing so should decrease vacuum pull at the needle up high in the carb bore. The bigger hole with them gone should activate needle fuel flow or 'pullover' slightly slower. That raised step in the middle of the part also seals the top of the main air bleed mixing chamber to fully premix needle bleed air better with fuel. But if the expert says so, I buy it..........it may have more effect on a CV type than direct because of the whopping greater open area with slide fully closed. I'll have to try it sometime.
Or maybe dirtdigger is saying that he just never uses the NEW part but DOES use SOMETHING there. Myself I always use a part there.