Well the hairnet is going to prevent a lot more hair from potentially entering product. I know in my operation (artisan cheese) they used to use paper caps (just like the one you posted), but now we use hairnets. At least in the US, the rules are slightly different for a production facility versus a more retail operation. When I worked in a grocery store, we just had to have our heads covered, either with a hat or a hairnet. Now after I have been in manufacturing for a few years, I have only seen hairnets. I have seen some videos of people in foreign countries that wear hats/caps instead of hairnets. I think the biggest thing is that you can say that you are protecting your product from contamination. I might look into your local regulations for what is required for head covering. Although a cap looks nicer than a hairnet, the hairnet will definitely keep more hair out of your product.