A person will only put 3 words on a topic, but it looks like they put like 3 paragraphs because of their signatures
^ Another reason to allow signatures to be toggled. If such an option is implemented, the mods could prevent abuse as follows:
What the mods can do with signatures off but not on:
-Detect short posts that are spammy
What the mods can do with signatures on but not off:
-Detect filler to hide spam
-Detect inappropriate signatures
How a user can abuse signatures if signatures cannot be turned off:
A user can use a long signature to hide spammy posts because the post will appear long and non-spammy to mods. While the mods might determine such a signature to be off-topic and therefore still spam, it will be easier to detect spam if the mods can turn off signatures.
Conclusion: I do not prefer signatures, but if they are implemented, it is necessary to implement toggling of the signatures. Signatures are annoying to some users and can be abused.