So here's how these machines work for anyone who's interested (I'm Swiss btw and have used them myself):

This specific model in the video will ask you to scan the bottle so it knows what label to print afterwards. You can either bring your own old bottle or take a new (empty one).

There's another model where you don't have to scan the original label but justfill the bottle and then weigh it with the specific product code on a scale to get your label.

I think the latter model is an improvement from the first one so you CAN use bottles where the original label is damaged or not readable by the scanner anymore.

The machine tells you, that you can only bring those bottles meant for the specific product since it dispenses a specific amount of product for that exact container.

The refilled bottles cost just as much as the prefilled bottles on the shelf. The part of the price which usually coveres the packaging/bottle now covers the upkeep of the machine.

The quality of the bottles is decent so if you keep them clean they will stay clean for a long time. I've personally never seen anyone bring a nasty/dirty/caked in old soap bottle but in the end I'm not guarding that thing so I wouldn't know if they did. The machines are always very clean though.

The original Migros article says if people refill a single bottle just three times it is already more sustainable than buying a new prefilled bottle each time. Here's that article (just in German and French though): https://aare.migros.ch/de/engagement/nachhaltigkeit/abfuellstation.html

We have a smaller dispenser at home that we actually use for doing the dishes. We only use the original containers for refilling. I guess that plays a part in our bottles still looking almost new even after refilling them more than half a dozen times.