I would argue that it helps with more than the other comments suggest.

The difference in writing (which I don't think is simply a matter of simplification when comparing Kanji and Simplified Chinese), is typically not a problem because of the ways characters are made up on Chinese.

Consider (japanese/chinese) 記/记, 設/设, 語/语, 計/计 and 説/说, by learning that single simplification of the 言 part you already recognise a good amount of characters in Mandarin (there are many more of those in the list). In fact, in many cases a learned reader can just guess the meaning of the other without having to learn them in the first place.

Many of the meaning of the single characters are the same/similar between the two languages. Even in cases where meanings have diverged between Japanese and Chinese, having and understanding of the single characters that make up more complex phrases still helps a lot in terms of guessing meaning and context.

Also, 恋人 doesn't necessarily, and usually doesn't, mean wife/husband in Chinese, its meaning is very similar to the one in Japanese.

Edit: Forgot to mention that if you are interested in seeing the difference between Japanese and Chinese for the 777 characters, simply copy-and-pasting the list into Google Translate as Simplified Chinese does the magic. Running them through a `for` loop shows that there are 184 characters that are not the same between the two languages; I estimate that there are roughly 40% of them that's on the level of 麺/面.

I found it interesting that Japanese people did better with traditional Chinese characters than with simplified Chinese. This makes sense because while some Japanese characters are simplified forms of traditional Chinese characters, they are often simplified very differently than the simplified Chinese forms. Japanese people might encounter the traditional characters in old books, but are unlikely to learn the simplified Chinese form unless they specifically studied Chinese.