Well as someone that has done this I'm not sure??? I sold my entire collection about 10 years ago and used it as a down payment on two homes, one as an "investment" rental property and one as our main house. Now we all know what happened in 2008 and I lost my A$$ on both and ended up short selling both to get out from them (I'm not talking like 50k loss, on our main home we lost over 250k..
) Now having said that there was no way of knowing it was going to happen or if it will happen again but after what happened to me I wish I had my cards back..
As someone above posted the cards are liquid and much easier to sell then a home. Now if you can sell all your cards and pay cash for the house that's a different story.