Purism runs deep in salvage culture, which is why reproduction hardware carries a bad name it doesn't always deserve. If old is good, the thinking goes, then only original will do, and a reproduction is a lesser thing, a fake. But a good reproduction is often the honest choice, and sometimes the better one.
When originals run out
Start with supply. Originals are a fixed and shrinking pool. If you need four matching sconces and two survive, or a consistent run of hardware for a whole house, the originals may not exist in the numbers the job requires. A faithful reproduction, made in the same materials to the same pattern, lets you finish without hunting for years or settling for a mismatch. Often the alternative to a reproduction isn't an original. It's nothing.
Safety and honesty
Safety is the other half, and it decides anything wired. An original fixture comes with old wire, old sockets, and insulation that may have dried inside the arms. Bringing that up to a standard you can trust takes real bench work. A good reproduction is built to current safety from the start. For a part that has to be reliable and pass inspection, building new to an old pattern is the responsible thing to do.
A reproduction only becomes a problem when it's passed off as original, aged to fake a past it never had. Labeled for what it is, a faithful copy in the right materials does honest, useful work, filling a set, matching a run, safely holding a spot no original is coming to fill.
Salvager's Note: The real question isn't "original or reproduction." It's what the job needs. For a matched run, or any fixture that has to be wired and safe, solid brass reproduction often beats a mismatched or unsafe original.