VWs and Audis have long had issues with their ignition coils. The 1.8T engine probably had the most well publicized issues when they were new. VW engineers struggled to come up with a design that could endure the harshness of their environment. The latest revision (06A905115D) is the best thus far, but they’re not guaranteed to last forever.
When a coil fails, raw fuel washes down the walls of the cylinder, gets into the oil pan - diluting the lubricity the oil, and damages the catalytic convertor. This is why when the check engine light (CEL) flashes, you need to pull over and shut the engine off as quickly as possible.
It’s always a good idea to have one or two coils in the trunk of the car, in the event that one fails while away from home. Repair tends to be quick and easy, and could save hundreds of dollars in towing charges, and lost time.