Property, I understand that, and I see the point, but this is child tax credits I'm talking about here,not working tax credits. Child tax credits shouldn't need to exist in the first place, but unfortunately there is a real need for working tax credits, and in the case of those, I'd agree with your point.
The majority of families that own their own home also own great big mortgages. They are always going to need housing, so while I see your point, I can't see the logic of turfing someone out of their home so that they can either live in an owned property that is too small for them, or to make them start private renting because they would be unlikely to get a council or HA home.
Benefits are there to help people that have fallen on hard times, and a family that has managed to get a mortgage and have equity in it are more likely to have been in a good situation and then need help than a family who has had children before they have got enough money for a deposit on a property ( assuming that that's what they want to do because that's what we are talking about here). That's what welfare is supposed to do. Help people who have fallen on hard times, not prop people up while they have children before they have the capability of housing and supporting them.
Cash savings are different to equity because they can be easily accessed without making a family move away from their home or jobs or schools.
Someone that is forced to release their equity will still need housing. Someone that is forced to spend their savings will just be spending their savings, there is a big difference between the two situations.