Bizarre Pricing?

Today I have been looking into subscribing to Caller Display with BT. It was going to cost £1.75 per month, but I decided to do it anyway. Just before I did, I noticed that it came free with "BT Privacy at Home". I expected that to cost even more that Caller Display, so I almost didn't look at, but I'm glad I did - it is actually free! Not that you really get anything else with it, apart from getting registered on the Telephone Preference Service (TPS) which is free anyway (and a good thing!).

Why would anyone pay £1.75 per month when they are giving it away for free? Sounds silly to me, but I'm not complaining!