Radiant electrical heat (hookup and conduit)

I'm installing a new electrical heat in the master bath remodel. My last contractor routed all the wires for me and now its my turn. Manufacturer specs say to route the power wires through conduit and the temp prob hammered. We didn't do this before (mainly because the wall is already finished. I'm curious if this is needed because I don't see an option post rough-in.

Secondly the power says that it requires a dedicated circuit. I'm positive we didn't do this before and its it necessary. My plans are to spline off of a very nearby power outlet. I have a 120v mat and a 120v thermostat. Is it okay to just spline and run to my new box then hook it up?