Snow load on a temporary structure is also a liability question: a collapsed or damaged shed on a public sidewalk becomes the business's problem and potentially the city's, whereas a patio that gets packed away each fall carries none of that risk for most of the year it would otherwise sit empty.
The clearing obligation is the other side of the same bylaw that already requires a homeowner to clear a residential sidewalk, and a business that leaves a structure blocking that clearance risks the same kind of enforcement, plus the added cost of a $400 to $600 inspection if the structure's footings are ever questioned by the city.
Saskatoon's climate settles the argument in practice more than any policy debate does: a structure that only pays for part of the year and is a liability for the rest usually is not worth building. Get your hand-reviewed valuation from Joel Dyck.