Color slide film has much less latitude than negative film. If the exposure isn't "nailed" within about 1/2 stop it can easily result in photos that are either over-exposed (high lights blown out - just clear acetate film), or way too dark. I've shot a lot of color slides over a period starting in 1965, the most consistently acceptable results I obtained were after Nikon introduced their "Matrix" metering.
Exposure can be corrected within limits when printing. Slides are the finished product, and their appearance is determined at the moment of exposure. As Jim says, there is not the latitude of negative film. That puts the burden on the photographer to get it right in the camera. The plus side of that burden is the ability to have complete control over the image, and the ability to exactly produce that part of the look desired which is influenced by exposure.
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.