I wouldn’t exactly call myself a speed-runner (I don’t go max-speed), but I do go fast, and and also just power through all lessons. I use no scripts.
But, I did self-study Japanese several years before WK, so I know a lot of vocabulary. Even now on lv 30, I mostly encounter stuff I know. So, for me, vocab-lessons are done before they start almost.
That’s not something someone encountering most items for the first time can do. I think I’d then take my time to digest all the new info, and not rush things. Better to make sure things stick, rather than having to go back an redo lessons because it’s all mixed up in my head at that point. ^^;
You are absolutely right in that you shouldn’t skip the vocab lessons. They are very valuable to make the kanji stick. ^>^