Surcharge for installing large-format tiles

Something can always go wrong in dispatch.

Would have, would, if.......

One feels more comfortable with online shopping, the other when buying on-site. I think we should just leave it at that.

No, we shouldn't. I buy every lamp online, it's no pressure if something doesn't fit. But if I get something wrong or broken or too little... the tiler will thank me. Especially since tile work usually includes consultation. That should also be appreciated.

No, we shouldn't.

Ok, I will still buy it from the cheapest source and I won't go out of my way to find a local dealer who might offer the same price.

Well, at the local tile dealer I was able to take various tiles as samples and first test them in the apartment's light, test them with my furniture, test them with the planned wallpapers, etc. The tiles that I eventually chose would not have been cheaper online anyway.
EDIT:
And, you end up creating your own construction site, because you are then responsible for ensuring that the tiles ordered online arrive in time for processing. And also not too early, since otherwise they have to be stored somewhere.
You are planning a huge house and then you want to deal with such delivery problems?

A problem with online tiles might possibly be reordering. It can happen that the online retailer does not get the same batch again. You don't know whether they store it themselves or buy it in after an order.

As if the tile dealer keeps everything in stock. But the pros and cons list is diligently maintained and there is certainly a lot of truth in it. Whether, for example, the coordination effort for the delivery is worth the mentioned extra cost (in the range of several thousand euros) is up to each individual to assess – 200-300€ shipping won’t change that either, if it even applies.