makers mark scraped off - why?

I have a nice piece of london sterling from 1798 with all hallmarks, but the maker’s mark has been clearly and fairly crudely scraped off. any idea why?

Possibly it came into the hands of a competitor who wished to sell it - but not with X’s mark on it. We can only speculate…

does it affect the value much?

Probably not much - it depends how much of a mess it looks.

great. thank you very much