They look related, and they are built to completely different standards, which is the single most useful thing to understand before buying either.
An event marquee is designed for short, supervised, seasonal use. It goes up for an occasion, comes down before winter, and the wind and snow cases it is designed against reflect that. Nobody is expecting it to stand through a February gale unattended with stock inside.
An industrial tent is engineered as a building. The frame is calculated for the wind and snow loadings at your postcode across continuous year-round use, the structural calculations come with it, and the fabric, fixings and anchoring are specified to match. That is what allows it to hold stock, house a process, and be insured accordingly.
The practical test is duration and contents. If the structure will stand through winters, be left unattended, or hold anything you would mind losing, it needs to be an industrial specification. The cost difference is real but modest against the risk.