I watched this film on a DVD that was rammed with short films from the period. I didn't watch all of them as the main problem with these type of things that their value is more in their historical novelty value rather than entertainment. So to watch them you do need to be put in the correct context so that you can keep this in mind and not watch it with modern eyes. With the Primitives & Pioneers DVD collection though you get nothing to help you out, literally the films are played one after the other (the main menu option is "play all") for several hours. With this it is hard to understand their relevance and as an educational tool it falls down as it leaves the viewer to fend for themselves, which I'm sure is fine for some viewers but certainly not the majority. What it means is that the DVD saves you searching the web for the films individually by putting them all in one place but that's about it.
Planktonrules says, had this film come later it might have been of no value but in 1898 it was part of early development of cinema. However I think he does it a disservice because this was a period where some films were still simple shots of normal action which relied on the novelty value of the audience seeing it on the screen more than anything else. However to me the Miller & the Sweep is an interesting piece of comedy because of its simple visual gag. Not particularly funny, but this film has two extremes and then sees them essentially discolour one another. The miller is white and gets turned black by the coal dust from the miner and vice versa due to the miller's flour.
It is not hilarious but it is a nice idea and the delivery is good in that the miller is very clean and white, while the sweep is very black an effective juxtaposition. Not great then but I liked the use of the clashing colours and the fact that the look of the film had been designed and delivery as opposed to being a shot of an event.