I think I have posted this before but I will post it again.

There is advantage in using BA Holidays if it meets certain limited criteria.
Yes you get all the benefits such as paying a deposit and then paying balance much later and all the other benefits posters above have identified.

However, there are some big disadvantages
1. If you are a 5 star hotel traveller then their selection of 5 star hotels is often poor to non existent.
2. If they do have 5 star hotels then very often the price they quote is more expensive than what you could get by booking direct. In the cases I looked at in detail, the difference was thousands more expensive with BAH than direct. As others have mentioned you typically lose all the hotel benefits. plus any spend points This can be considerable in some cases.

For this reason, I have only ever once booked a BA Holiday with a Hotel which was a Hilton and luckily they did honour the free breakfast for Hilton Diamonds. All other BA Holiday bookings have been just Flight and Car with the car hire from Avis.