My organization performs written consent for cryotherapy. I've learned it is significantly important that your consent practices match whatever is outlined in your practice's policy and procedures. We have been reminded of this in most of our recent Joint Commission visits for accreditation. I would also recommend thinking about your consent practices in regards to risk of outcomes for "procedures" and not difficulty/time to perform the procedure. Example: Cryotherapy is certainly easier to complete than skin biopsy and seems less invasive than electrodessication but the risks may not be significantly different.
Ultimately you're getting into the legal realm here, where I've found definitive answers to question even more rare than in medicine.