It is usually illegal to give legal advice or represent someone without being a lawyer, so this disclaimer is meant to protect yourself against claims that you're doing so. I think.
> It is usually illegal to give legal advice or represent someone without being a lawyer
This is not true. It is usually illegal to give someone the impression that you are a lawyer when you are giving legal advice (it is fraud.) So careful people lead by making sure that no one has the impression that they are a lawyer when they are giving legal advice, and lawyers who are just talking off the top of their head and not being paid warn you that they are not giving you advice as a lawyer (i.e. they are not working at this moment as a lawyer.)
People who are not lawyers give each other legal advice all the time. It's a good thing if the advice is good, and a bad thing if the advice is bad, but not a crime.
