Good afternoon! Eating crusts from wounds is unaesthetic and unhygienic, since it is a waste product of blood cells (platelets, leukocytes) and bacteria, as well as dead skin tissue and subcutaneous fat. The use of crusts (scabs) does not bring any particular harm to the body, since there are special enzymes in the oral cavity, stomach that disinfect any contaminated biomaterial that gets inside the body, but there is no benefit from this
Remember! Any food should at least be washed before use. If you first wash and disinfect it, then why not. Bon appetit.