A scraper only works if it is sharp. Once the edge rounds over it stops cutting and starts smearing, pushing wax along the base and pressing it into the structure: the opposite of what scraping is for.
Plexi scrapers are the standard for removing wax and should be sharpened every few pairs, which takes seconds with a sharpener. Steel scrapers are for base work rather than wax: levelling a repair or taking down a raised patch, where a plastic scraper would just skate over it.
Thickness matters more than people expect. A thin scraper flexes and follows the base; a thick one stays flat and cuts.