What's been confusing me about what you've been saying is that you've
been talking about checking your WB in LiveView. If you're just saying
that you're happy with a JPEG that's using one of the standard WB
settings, then sure, you can use the image right away, & what you're
saying makes sense.

Well, I was going more deeply than that. The Live View lets you fine-tune
the white balance fairly quickly.

If you run through the range of "conventional" color-temperature settings
under fluorescent light, * you'll see that it's rare for any of them to
closely approach neutrality. Some degree of green/magenta adjustment is
needed, and it's quickly set in Live View. (It is on my Canon, anyway.)

The issue that neither of us has discussed is whether what we see in Live
View is trustworthy with respect to accurate white balance. You need to
display the images on a calibrated monitor and see whether what /looks/
properly white on the camera's LCD actually is.

* Ordinary fluorescents, not those designed for photographic use, which can
be quite good.


OTOH, I've been talking about a *real* WB, which requires either a
white card shot to set a custom WB, or tweaking the WB of a RAW
file on my PC.

For which the WhiBal card is a good choice. Take a photo with it under the
same lighting, then "eyedropper" a sample of the card into the image you
want to correct.

Google "whibal". The site has a lot of useful information.