You are right. But some people misuse that opportunity. Specially account sale and scammer.
This point has both positive and negative aspects.
Positive:
Locked self-moderated topics: "Is a good sign for scammers" Awareness of these posts has increased, so there have been fewer confirmed scams on these topics.
Negative:
The excellent use of this feature depends on who publishes the topics; Many use it carelessly.
OP add this
The selfMod bit will now be permanently cleared when a non-mod moves a topic into a section which doesn't allow selfMod.