Actually, lower voltage @ same wattage = higher current draw. (W=V*I)

Say it takes X amount of watts to create Y amount of light. If you use 120v
to do it, you will draw only 20% of the current you would draw creating the
same amount of light with 24v. The amount of power consumed is the same,
but the current is higher. In general terms, higher current = more energy
lost as heat instead of light (lower efficiency) and more electrical 'wear
and tear' on contacts and switches.

So WHY do they use low voltage for these things? Mostly for 'code
satisfaction'. 120 needs to be in sub surface grade conduit if it's going
to be buried. The low voltage stuff doesn't. The transformer that's
stepping it down will only pass X amount of wattage before toasting itself.
It's made to satisfy the lighting needs and a little margin for error.
Short the circuit out, or otherwise try to increase the current draw, and
before it reaches a 'dangerous level', the whole thing shuts down.

That's why the homeade 'de-squirrelizer' on the post holding out bird
feeder runs on 12 volts. Max current flow through the line is 4 amps.
Enough to stop a squirrel, but not enough to knock down a person (as I can
attest)

RichZ©
www.richz.com/fishing