Establishing your business as an LLC has benefits even if one does not have personal protection if you, as the single member, are the cause of the incident. For instance, your client is putting their gear together and their tank falls over causing the valve or tank to rocket against a nearby parked car, or worse...it strikes a person. In the event of a lawsuit due to this incident, your assets are severed from the business unless it is established that your personal negligence contributed to the incident.
OP, regardless of whether you establish your DM business as an LLC or remain a sole proprietorship, be sure to brush up on what you can deduct from your taxes...use of your car, gear, phone, certain meals, insurance costs, costs to maintain certification, continued training, and more can be tax write-offs as business expenses.
-Z