A professional wheel is bought to run for hours a day for decades. What that buys over a hobby machine is mass, a motor that does not care about the load, a pedal that lasts, and a manufacturer who still supplies parts in fifteen years.
Mass and stability
Studio wheels are heavy, and the weight does real work: it keeps the machine still under the sideways force of centring a large amount of clay, and it damps vibration that a lighter frame passes into the pot. Anyone who has moved between a hobby wheel and a studio wheel notices this before they notice the motor.
Duty cycle
A hobby wheel is designed for intermittent use and a professional one for continuous running. That difference shows in the motor, the bearings and the electronics rather than in the stated capacity, and it is why college and studio wheels survive treatment that would finish a domestic machine in a year.
Serviceability
Professional machines are built to be repaired: pedals, belts, bearings and controllers are replaceable and available. Over twenty years that is worth more than any specification, and it is the reason well-used studio wheels hold their value on the second-hand market where hobby machines do not.
Whether a home potter needs one
Usually not, and many buy one anyway and are glad. If you throw large forms, throw for hours at a time, or intend to sell work, the extra mass and duty cycle pay for themselves. If you throw mugs at weekends, a good mid-range wheel does the same job and leaves money for clay and a kiln.
Questions people ask about pottery wheel
What makes a wheel professional?
Mass, a motor and bearings rated for continuous running, a durable pedal, and long-term parts availability.
Do I need one at home?
Only if you throw large or throw for hours. A good mid-range wheel throws the same pots for most people.
Do studio wheels hold their value?
Yes, because they are repairable and parts are available, which is why used ones sell readily.