Rehydrating dry yeast

I'm sure there's a thread on this buried somewhere in this forum, but I couldn't find it in five minutes so I beg forgiveness for posting it again.

Why do some dry yeast packets specifically direct the brewer to "pitch directly into wort"? Isn't the conventional wisdom that it's always better to rehydrate first? (I work in a winery and we always rehydrate before inoculating). I've been pitching dry yeast directly in my homebrews and have no complaints so far, but am wondering if it will improve my beers to rehydrate and/or do any other preparatory steps when I use the dry stuff. For context's sake, I'm about to brew a barleywine and have two 11.5g packets of Safale US-05 for it.

One reason to rehydrate is to check viability. This is how I discovered I had some of the bad Nottingham a while back.

Here is a decent rehydration method from John Palmer.