Dan doesn't seem to like much of anything. I like electric pumps "sometimes." They can help with vapor lock problems, which has been aggravated by todays alky gas.
You definately want to put an oil pressure safety on the engine, and an inertia "crash" switch doesn't hurt, either. Thanks to our new EFI cars, finding usable oil safety switches or crash switches is real easy. Ford Rangers are one source of crash switches. Toyota used to use an oil pressure switch that was easy to deal with.
You really should run the pump through a relay, so all these additons are easy.
Here's one diagram, showing one generic way to add a pressure switch. In this case, they are not using a relay, so the item marked "pump" would be the "pump relay. Here's how this one works. The connection to the starter solenoid goes to the nc (nomally closed) contacts. So when you are "on the starter," current feeds from the starter solenoid, through the nc -c (common) contact to operate the pump. If pressure should happen to come up, either from the engine firing or "on the starter," pressure will change the switch over to the n.o. (normally open) to c (common) contact and this power comes from the "igition run" circuit.
On Moparts, "ignition run" is dead during crank, so the pump will actually QUIT if you are cranking and the engine develops enough pressure to trip the switch.
This should be no problem, because the pump should already be primed, and there should be enough fuel in the bowl to run for the .00000000001 to 2 seconds that this is going on.
Back "when I was a kid" I used to run series pumps as you describe, and they worked OK. The purpose was to give a little boost for the 440 back then. It actually saved my a$$ one time when the mechanical pump failed. Just bypassed 'er and used the electric pump.
Incidently, running series pumps OF CERTAIN TYPES does not jack up fuel pressure. This is because the older "pulser" pumps build pressure the same way as the mechanical pumps---they pump gas on a spring. So the camshaft "cocks" the mechanical, the electric solenoid "cocks" the electric, and the spring inside returns the piston or diaphragm, pumping the gas. This means that fuel pressure is regulated by the spring, not the solenoid, and that as the electric pump builds pressure, the mechanical simply "floats" the arm off the cam and stops pumping.