That picture is too small and blurry to even make out individual scanlines.
Is that a game that's natively 480 lines? From what I can see, the scanlines there are very thin, which is appropriate for actual 480 line content and should look great.
However, it will not look best with something that's natively 240p (most arcade games from the 70's, 80's, and 90's). What should be around 240 lines will be doubled to 480 lines (and not completely smoothly as most of these games are not
exactly 240 lines), meaning that instead of one nice distinct scanline in between each line of resolution, there will be one very thin one in between each line, AND another one cutting in half what should have been a solid line.
Proper 240p:

So.... with a sharp enough monitor you can see
some thin scanlines in 480i. They'll probably be great for something that's
supposed to 480 lines, but they won't be good for something that's supposed to be 240 lines (95% of MAME games). They will be thin, there will be twice as many as there should be, and they will not be in the right places.