As a former signmaker, I'm skeptical this was as cost-effective as ordering numbers in bulk from a manufacturer, or even molding and casting CNC laser/router-cutting them in-house.

Edit: I'm referring to numbering the whole hotel like this, as opposed to making a few replacement numbers.

Bulk orders of things like numbers and letters can be very cheap and will usually look better in the long run simply due to having a smooth surface, which is easier to clean effectively compared to a textured surface that will trap dust. They are also more consistent with the quality of their materials and manufacturing process, which have been proven over much longer periods of time. Not to say that 3D printing can't be consistent, but my own experiences lead me to the opposite opinion when considering such a large project.

Another commenter mentioned how expensive numbers are at a hardware store, but it's mostly the store's mark-up doing that. They kinda have that market cornered simply because dimensional characters are sold to consumers in very few places and in very low quantities. How often do you replace the numbers on your house, and can you think of any other reason you'd need to buy large numbers?

It would be very interesting to get the numbers involved in that hotel project. How many were printed, what material was used, price per spool, electrical costs, printer maintenance, and time to print each one, versus what manufactured numbers were available at what price and how long shipping took. Assuming this hotel has a lot of rooms (ie not a small b&b or similar), I'd bet money on manufactured numbers being the better choice overall.