The short answer is because I like building antennas.

The more detailed answer is that I've got a forty foot long rotatable
doublet made from some of those 20' crappie poles, and I want to match
that. Making a fan dipole out of it would not really be possible. I'm
already going to do that for 40/80 for FD, but the doublet will work
well for the higher bands.

I'm eventually looking to have a 40-10m inclusive extremely lightweight
rotatable antenna with good efficiency on an easily erected mast. On
40m/30m I already have a loading and matching coil to make it a "shorty
40" style shortened dipole. For 20 and up I don't need loading I just
need to match it. It's going to be nice because it is tree
independent. I could set it up in a parking lot on a light mast if I
needed to.

Simple is not my style for field day. In a pinch I'll throw up simple
dipoles. In a real emergency, I'm not going to go fancy, I'm going to
go simple and resonant.

For field day, though, I like to put weird things up. I built a 3
element 15m yagi one year just for FD. The year before, I built an
aluminum tubing trap dipole for 10/15m.

If 15 and 10 are dead as I expect they might be, I might even turn the
crappie pole antenna into a delta loop for 20 only.

73,
Dan
N3OX