True. Certainly not ideal or the safest. I'm also surprised the standard plan is to put everything in the dirt below the slab. When I build a house from scratch everything will be easily repairable. Either full access or large conduit to pull new PEX or wire.I would never run water through the attic. I have a two high efficiency heaters in the attic. Both require condensation drains. The drain on the unit that heats the upstairs has frozen several times. I have insulated with pipe insulation then wrapped with fiberglass.
When that drain feeezes it shuts off the heater. Terrible design to be located in an uninsulated attic.