sharpening the built-in jigsaw saw blade using a cutting grinder 

the content of the video only shows the jigsaw eye testing before grinding, grinding process, and testing after grinding.
An example of a built-in jigsaw blade that I grind is the Benz jigsaw default saw blade.
maybe this video just makes it difficult for people who are quite easy to find shops that sell jigsaw eyes in their area but for me it's hard to find a shop that sells jigsaw eyes in my area, by grinding the jigsaw eyes the results are quite helpful