I see your point, but imagine a situation where I robbed bank for a million dollars. Should I be able to use that million to pay a really good lawyer to defend me in court? And then after I'm feeling guilty I just throw my hands up and say "well I don't have that million anymore, good luck collecting it from me while I'm in jail."

At the very least, I believe the assets would be returned to them if it turns out they are found not guilty. So they are seized but not gone for good.