One FP usage means a heck of a lot of Lock-Focus-Recomposing. Sloopy camera workflow, to be sure. This bad habit means inaccurate auto focus, AND inaccurate metering too. If you want to do this while shooting F8 or down from there AND far from your subject/s, then the ill effects may not haunt your pictures. But for anything close and fast in aperture, Lock-Focus-recompose is a huge mistake.
Best practices for modern SLR camera workflow means utilizing the 45 or 51 or more focus points judiciously and as required, without the Recomposing.
It is far more quick and simple to focus with one dot all the time than it is to pick a new focusing point for each picture.
Sloppy camera workflow??? As opposed to pressing the button and twirling the dials to pick the point that is closest to what you want to focus on, which may not even be right over what you want to focus on anyhow? Focus/compose is way neater, faster, and more efficient. I find changing points to cause "sloppy camera workflow," and to completely ruin the element of timing, which is often EVERYTHING with small format shooting.
Bad habit??? No. It is a very good habit; a habit that saves time and prevents distraction.
Inaccurate focus!!!??? I've never had it, at any distance and any aperture. Then again, I do actually LOOK at the screen to see what is in focus even when using auto focus, so maybe I am biased...
Inaccurate metering??? How is this? You meter whatever you want in either case. Besides, do you think that what an in-camera reflected meter tells you the best exposure in the first place? I never use the things anyhow. Wish they were not even there. Most overrated feature IMO, as I opined early in the thread.
If ECF actually worked flawlessly, I'd not focus with one point and then compose...but it does not. Automatic point selection is crap, for the birds. (I hope we can at least agree on this point.) In a perfect, controlled, staged world, manual point selection is theoretically best, but far from it in most small format practice. One who doesn't do that much shooting of classically-small-format-suited subjects (things in motion, fleeting things, candid things, things that cannot be replicated, most importantly) might think that it is best simply due to the fact that it is not making them miss their shots, and because of addiction to features and to the instruction manual...but actually implementing manual point election in 90% of my real-world small format shooting situations takes too long, and
would not give better results even if it didn't take too long. IME, it only makes sense on a tripod, in which case I likely wouldn't have any need to use automatic focus. For any pic with which I am going to bother to fiddle that much, I am generally just going to pull out a medium format camera anyhow. One shot, one point, AF moved to AE lock button, focus/compose takes only a second or less. Choosing the point over what I want to focus on (if there is such a thing in that particular picture) takes longer, and
all the fiddling messes up my composition anyhow, so I still need to recompose.