Why do people often say “if anything, I’ll be in touch”?

People often say "if anything, I'll be in touch" as a polite way of saying that they will stay in contact with someone. This phrase implies that the speaker is open to staying in contact and is willing to do so if the need arises. It also implies that the speaker is open to any further communication that may come up in the future. This phrase is often used to show respect and to indicate that the speaker values the other person's opinion and wants to remain in contact. It also shows that the speaker is open to further communication and that they are willing to keep the conversation going if necessary. By using this phrase, the speaker is showing that they are open to any further communication that may come up in the future.