The user who posted the question, and consequently the second account that posted a garbage answer, were apparently attempting to troll and had been posting similar to other sites on the network.
Unless you were active on the other sites or intentionally checked then you would not have known.
Both spam and rude/abusive flags feed into the spam prevention system and will block users from posting more garbage. A single flag is unlikely to hit the filter but multiple generally will, especially if multiple users appear at the same IP, and it can be an effective temporary stop for casual trolls.
The main function of the VLQ flag from the users perspective is to push the item into the review queues, for other users to look at and action if necessary, and to point it out to moderators. In that it served its purpose.
After that it depends on what action needs to be taken as to whether other flags also get applied.
I doubt VLQ isshouldn't be used as a close/deletion reason that often, especially as we already have the "unclear what you are asking" close reason already. It is not really a close reason, and as it is only seen by other users the only options are for them to either vote to close or, if they have the power, vote to delete.
Spam/rude flags are "MAKE THIS GONE NOW!" While VLQ and similar are "Should we make this gone? Can someone help with this?"
If you want a mod or the community to look at it, then use VLQ or a custom flag. If you want it dead and buried them spam/rude. If you just want it closed then close it.