So for wealthfront and friends, let's say a family member is closing on a property purchase. You said you'd put in $500K. Closing comes and you try to wire the money over. But wait, it doesn't work.
1) First you have to sell investments 2) Trades have to SETTLE (T+2 or more)! 3) Then and only then can you initiate an ACH transfer. 4) It can only go to your own account in some cases (T+1/T+2) 5) Then you have to go to you bank and get a wire out (retail banks often have tight cutoffs or end up delayed if going online while they "approve" this). 6) This all can be stressful on closing day (agents calling, escrow calling, bank calling, your relative calling). Now you are not days but a week late.
vs
Talking with someone. They enable margin account if you don't have one, you wire same day, done or you can give your guys name to everyone to help coordinate if needed if it will be a bit late.