🚀 go-pugleaf

"It is universally (or very, very near to it) considered to be a bad
thing
*when* you don't want it. "

If you have the skills, you have grain or don't according to your
wishes. It's a matter of skill.

"It is universally considered to be a good thing to be able to choose
when
you want it and when you don't. "

Not at all. Most film photographers don't care that much, enjoying
their limitations. They make decisions and live with them. Most digital
photographers are also content to work within the limitations of their
technology, as for example with prosumer dslrs or digicams instead of
more serious equipment. Some film photographers always work with Leicas
and TriX/Rodinal, or restrict themselves to the narrow possibilities of
Velvia, or, as Ansel, using soft developers as an aesthetic choice.
Some digital photographers are content with 8MP dslrs in all
situations, despite or because of the fact that the images are usually
immediately identifiable as coming from that sort of camera, especially
in B&W.

"However, both film and digital SLR's allow you to choose ISO speed.
Increased digital "noise" being the "equivalent" of increased grain as
the
speed is increased. "

Speed and grain do not have a linear relationship in film except when a
person is unskilled or for his own reasons confines himself to limited
methods for various films. While many film photographers, galleries,
designers etc relish the look of whatever grain they choose to display,
its interesting that nobody seems to enjoy the look of noise in
digital. Thats probably because noise commonly looks mushy.  When more
visually-oriented (vs technically oriented) photographers start to
explore digital printing, some will inevitably start to play with noise
as a positive characteristic.

My own 800ei Neopan 400 in Emofin (as opposed to the same film at the
same ei in Rodinal, which I also enjoy) is approximately as grainy as
typical silver 100ei films in their manufacturers' recommended
developers, for example...grain size and character is simply a
craftsperson's choice unless he's incompetent. If a person has grain
and doesn't like it, that is either his bad luck or his lack of skill.