I've been there: I learned photography using film, and I recall, for example, shooting a test roll of 12 with the same subject with different flash setups. I had to carefully take notes, even sketches, for each exposure, and plan a set of things to try before getting any feedback.
Buying film was an expense. Developing it took time and effort, and a contact sheet (rather than printing all of them) gave a small window onto the results that I could view with a magnifying glass (and further inspection of the negative using a loupe, but it's negative so harder to understand).
With a digital camera, I typically shoot hundreds of exposures, and can even use auto-bracketing. If I get a bunch of junk I can just delete it all and it costs nothing.
When learning a technique, whether technical or artistic, I get immediate feedback on the results. For matters of overall exposure and composition, the built-in screen and embedded tools like histogram and zebra stripes is enough. You can take a picture, fiddle with the settings, and try again, and home in on the correct settings in a few shots. Likewise for overall composition and gross lighting. For more nuanced high-fidelity inspection of the results, the camera might support linking to a computer to show the last shot, or in any case transferring the images is much much easier and faster than developing film!
Furthermore, the dynamic range of the digital camera is larger than that of film, so you don't have to, for example, get the intensity of multiple flashes exactly right to balance the fill light and subject face lighting. The overall lighting effect might be easier to adjust in Lightroom than it would be to adjust one of the flashes and shoot again!
In short:
- Fast Feedback of results
- better feedback without needing expensive tools
- Ability to practice and experiment much more.
Even professionals, back in the day, would use Polaroid backs on their medium-format camera for setting up and adjusting, and only use "film" once that is done. They had spot meters for carefully taking measurements off the ground glass screen, to quantize the bright/dark values, before making an exposure.
P.S.
I had both film and digital bodies that take the same lenses and accessories. So, if I had the desire to shoot film again, I could set it up on the digital and then use the same lens and lights on the film camera for the final shot.
I say had, past tense, because both of my original EOS bodies (650 and 620) broke. It was not worth the cost to have the shutter mechanism replaced. But, I still use my original 50mm lense manufactured in January 1987.