That's a really good point. I'm using macOS and I tested -w option against a CSV file that is about 430MB in size and has about 18,000,000 words in it. The time was 0.989. When I ran wc2 on the same file, it clocked in at 0.943.

I wondered what I was doing wrong and came back to the comments section and found your comment. Ah.

Edit: interestingly, the newline count time was 0.458 with the macOS version and 0.943 with wc2.