Yes, you are correct. Coils need a constant power input to operate, power to coils is not intermittent. Providing your power through a relay and then putting a (kill) switch in either the power-supply, trigger line, or on some relays even the ground will work just fine. As for hiding the switch that's up to you, but put it in a place where it can be reached; you don't want to have the bike fall over with the engine running and not be able to reach the kill switch.
I started to write up an explanation of what relays are for with an example of a very good use of one, but it got to be too long and it would have bored the hell out of you. Basically you use them where one of two things has to be overcome. The first is long wire runs, but we don't have those on motorcycles. The second is to protect switches from burnout of the contact points due to high power passage, but we don't have that on bike's either. So there's really no place for one on a bike.
Long Version:
Here is a place where I used a relay for all the right reasons on a boat. On the boat the batteries were in the back, the controls were in the middle, and a large water pump was in the rear. The pump used a lot of power but to get power to it through its control switch required a run of wire from the battery to the console and then back to the pump itself - a run of over 30 feet of wire. Because the wire run was so long and the power requirements of the pump so great a very large ($$$) wire would be required to feed it. Also, there is a lot of power loss in 30 feet of wire.
In this case the use of a relay was warranted. By running a heavy power line through a relay in the back of the boat high power to the pump was maintained because the distance traveled was short and then a much longer but lighter gauge wire was used from the console to the relay to trigger it. In this case the relay did everything a relay is there for. I was able to use a light duty switch at the console because the trigger amperage was fractional and I was able to use a short heavy gauge wire between the battery and the pump so the pump got maximum power with next to no line loss. There is no similar power requirement on a motor cycle. All the power draws are low and the distance from the power supply to any one of them even including the routing to the hand controls and back, is short.
