Had someone else parrot this line to me the other day, but I remain unconvinced. Especially when vim has visual mode, and you often can make a select before doing something to it. v$ to select from cursor to end of line, then d to cut or y to copy. Is that not the sort of thing you mean? Is visual mode in vim just underused?
Recently I was trying to find a good way to delete from the current position backward to another character, like dT or dF followed by the target character. The trouble was they'd leave at least one character behind, either what I jumped to or what I started on. What worked how I want, and was still easy, was just using visual mode. Where "n" was the character to jump back to, I did vFn which selected from my cursor position back to the letter n (and including that n). I could then hit d and delete all of it, no extra character left behind from either end. I remember at first I was thinking "there's gotta be a way to do this without visual mode". Best I could come up with was hitting x after dFn or whatever to get the stray character. I think using visual mode is probably fine, though. Maybe if I were doing this type of edit a lot I could bind some key sequence to do it.
Would it be accurate to say you didn't use visual mode much in vim before you moved to Helix?