They were also conveniently available for us to watch, or sneak a viewing of. I remember the first of my viewings of Dracula came late at night when I got up and turned on the old portable TV near my bedroom. It had a broken antenna on it, and the wiring to the back of the tv was not great, but if you fidgeted with it, you could break through the static and get some channels, and some UHF. (...I know most of you have no idea what I'm talking about. I clearly come from some dark age of entertainment.) And as I moved the lousy antenna a bit, the opening of Dracula came into focus. A carriage racing through mountains.
It was thanks to Shock Theater that we all had these movies ingrained in us at a young age. Creatures of the night. Cinematic terrors, that by my childhood became more agreeable for the whole family to enjoy. How horrible!

Tod Browning had a good career as a director: London After Midnight (which was sadly mostly lost -- But I plan to cover down the road.), Thirteenth Chair (his first talking movie, and his first time working with Bela Lugosi), Freaks, Mark of the Vampire (with Bela Lugosi again), The Unknown, The Unholy Three, The Blackbird, The Road to Mandalay. Several of his movies were made working with Lon Chaney. They were good friends.
Chaney was one of the leading men they wanted to have in the film. In fact, it's one of the reasons that Carl Laemmle, Sr. greenlit the movie. He expected they could get Chaney onboard at Universal. But that didn't happen, as he stayed at MGM. And he ended up remaking Browning's The Unholy Three without Browning. Shortly after, Chaney died.