Alcor, for example, charges what amounts to a fee to perform the preservation and a fee to go into a fund that will be invested to pay for your ongoing preservation. "Not giving your family an additional $80,000 on your death" amounts to the same thing as "taking $X from them in perpetuity", but it's psychologically different. It's all about the cost-benefit analysis, whose outcome may be different for different people; some people just don't value their lives very much and are more willing to die the true death, some people have family who are getting on just fine without the cash injection provided by their death so are more willing to spend the money on preservation, and so on.

"Not giving your family closure" is something you just have to discuss with your own family. I, for one, would treat cryopreservation as effectively death with a rather unusual body-disposal mechanism, for the purposes of grieving etc; there's certainly almost no chance I'll see a cryopreserved person again before my own first death. For a family made up of people like me, that particular argument holds no water at all.