Employing outside aids - sensory substitutes, fidget toys, behavioral blockers - are not by rule good or bad. I am, however, thoughtful about when I recommend them. The key to me is whether they are being employed honestly and earnestly. Slapping them on yourself in an automatic attempt to stop your picking, pulling, or biting is different from putting them on after you have gone through the hard work of choice.
Our first reactions to our BFRBs commonly involve unanimous censure of, “You need to stop,” which differs from the personally and eventually attained, “I want to stop.” Beanies, vaseline, stress balls, and gloves should not be employed at times when you try to impose a No when you are honestly feeling a Yes (to picking, pulling, or biting). They have to be tools that merely support your decision for a different outcome in a BFRB moment. The root of change needs to be YOU because you will always be more powerful than any piece of fabric, cloth, lubricant, etc. (and thus can simply ditch any of these). They can and will not stop you unless you want them to! Furthermore, expecting these random things to do the work for you instead of because of you will maintain a belief that hope, power, and salvation lie outside of you when they do not.
BFRBs offer a source of comfort, so we turn to them as simply as a child would to their blankie or pacifier. For adults, choosing to go from comfort to absence requires commitment and possibly help. These outside tools come in and ease the burdens of follow through once you have surrendered to the reality of your BFRB, made your choice, and now can simply use some support. (Mindful awareness, internal reflection, emotional vulnerability, weighing of outcomes is hard work!)
I don’t believe anyone should have to “fight” themselves, and it is no longer “restriction” when you are giving yourself what you have resolved you want. Remember that these tools shouldn’t be exploited to “block” you, but embraced to aid you. Invoke them once you have arrived at a feeling in a BFRB episode that you truly want to desist and you don’t want to do it alone (because you don't have to!). Remember to leave time for the urge to pass, and that you can also involve PEOPLE and not just things.
Best of luck, devotion, and skill!