Later on, I realized what they were all for.
So to the OP, you just understand what profile signatures are all about so that you don't worry yourself much when you don't have some necessary reasons for it. But then, you must understand that you are still a newbie so at your rank, you will be unable to update that feature not until you ranks up probably from Junior rank and above.
Meanwhile... It does not really mean that because you have achieved a great rank that it is a compulsory to update your profile signatures. You really need reasons for it as for the signatures, they are of either to promote projects, companies or personal ideal or obligations.
I just wanted you to understand the validity of profile signatures.