He's right. All you are doing is substituting switches/relays for the physical act.
You're making and breaking the AC connection. You could do this by flipping the switch on each component or by pulling each AC plug from the wall. You're doing the same thing, just in a timed electronic manner. The end result is capacitor discharge during down-time and increased levels of in-rush current, which strains the transformer, rectifiers, regulation circuitry ( if any ) and caps. Using your home-brew sequencer simply takes the physical wear and tear off of the AC plugs and power switch of each component without achieving anything else. Sean