Both get you from A to B. Here's how booking, vehicles, and pricing actually differ between a black car / chauffeur service and a rideshare app.
Black car service is reserved in advance with a confirmed chauffeur and vehicle. Rideshare is typically hailed on-demand, matched to whichever nearby driver is available.
Black car service uses a standardized fleet of professional vehicles. Rideshare vehicles vary widely by driver — make, model, age, and condition are not standardized.
Black car service is typically quoted or billed on a set structure. Rideshare pricing can fluctuate in real time with demand (surge pricing).
Rideshare is built for spontaneous, short-notice trips. Black car service is built for planned travel where a confirmed vehicle, a professional chauffeur, and predictable timing matter — airport transfers, corporate travel, weddings, and events.