The reason is it might help the sale to give a valid reason. 'I'm selling because they're rubbish' is going to put buyers off, right? And if you don't give a reason for sale, that possibility is still in the buyers mind.I never use that stuff. I see no reason to explain my reason for selling. If buyer needs that I just say I am selling them, do you want them? I have had 1 issue when doing that. A Karen was nagging me for a reason. She asked 3 times and insisted that I answer her question. I told her flat out, "I am selling, do you want them?" I let her walk. Bigger fish to fry I think.
So my advice always give a reason, good ones include:
1) Upgrading
2) Don't want to sell but need the money due to unexpected bill, family holiday, wife is sick, lost my job etc
3) Moving house/moved house and not enough room in the new place
4) Emigrating, can't take them with me