It does visibly use a few more tokens in the short term. But it hurts Claude's ability in the long term if removed because it has to either think more every time it encounters that section in the code (more invisible thinking tokens used), or there's an increased risk of making a maladaptive change without context. Heck I've been bitten enough times already by it, though more recently it's cross project concern where Claude rediscovers some root cause that was already found and documented (I have it save a centrally-located writeup for things that took serious work to learn, when I remember, but I still need to make that knowledge pool known to other agents/sessions without having to manually prompt each time) elsewhere.

Problem is today's LLMs don't have the long term memory that humans have, and so remembering the reason behind a given change/decision has to be preserved in some way if it's non-obvious. Hence why there is {AGENTS|CLAUDE}.md, the auto-memory system, and 1001 variants of memory implementations in the wild. All are trying to ensure that LLMs can have the context they need at the location and time they need it. And you want to block Claude from using a technique that it natively finds helpful.

Confusion usually surfaces immediately, so it can be steered properly. Being sure of a decision that turns out to be wrong usually means a bug that could bite when you least expect it.

It isn't about making readers not think about foo. It's about biasing thought about foo in a particular direction. And I've seen it work multiple times: agent mentions it encountered X comments in the code and revised its action as a result (yes, I read live agent transcripts).