For houses building a collector proposition, a closed numbered series does something a standard run cannot: it makes the specification part of the object rather than an internal document. Each piece carries its number, the series is closed at the stated count, and the material batch is reserved and exhausted rather than carried into the next programme.
That last point is where most limited editions quietly fail. If leftover material from a numbered series appears in general production the following season, the series was not limited in any sense the customer would recognise. We exhaust or retire the batch and record which, and we will state that in writing where a programme depends on it.
Numbered series also change the documentation. A collector piece should leave with material disclosure and, where the value justifies it, independent laboratory analysis — not a certificate we printed ourselves. The difference costs little at this price point and it is precisely what a knowledgeable buyer checks.