In the late 19th and early 20th century, Georges Méliès was a very successful filmmaker. Much of it was because Méliès was originally a stage magician and he thought like one when making films. As a result, many of his films look like magic shows and the director used a lot of camera tricks to make things seemingly appear and disappear. Soon, others began copying his films....and among them, the Spaniard, Segundo de Chomón, was among the best....though his versions of the great master's films often were second-rate in quality.
"Le Spectre Rouge" is one of the best Chomón films to watch. This is because he crams every sort of camera trick into the film plus it's all in the form of a magic show. And, to get it all there, the film is about 9 minutes in length....which is amazingly long when the average movie was about one to two minutes long! As a result, you get a great homage to Méliès...one where you can see a lot of film footage showing his techniques which Chomón copied. This footage is all in the form of a weird caped skeleton-demon performing magic tricks until the tables are turned on him.
As far as how watchable all this is, it depends on you. If you love very, very early films by all means watch. Otherwise, you might find it tough going even if the film is technically brilliant.