Bla Bla Car Experience?

Why not take the train?

It's a ride share app, so people planning to drive from A to B post their trip if they are willing to accept passengers. So it can be a bit of a lottery, especially when it comes to luggage.

But apart from that, I also wonder why you're not just taking the train?

With Blabla Car you will be dependent on there actually being someone doing that route at the time you want do to it. It is quite possible that once you signed up and submitted your interest that it takes a while till you are matched with someone (its basically carpooling) going the same way, and it may not be at a time, or even date, convenient to you.
If you want to get from Vienna to Salzburg in a predictable way take the train.

" I’m not sure about safety " - If you're concerned about safety , why would you ride in a car with a private , unlicensed total stranger who may be a reckless or otherwise irresponsible. driver ? Needless to say there is frequent , reliable , and comfortable rail service from Vienna to Salzburg , from both Oebb and Westbahn .

Thank you everyone. My suspicions of this option have been confirmed. Not worth it to save some money. The train it is!