Pop sci-fi seems to be fond of intermediate-mass black holes (EG Interstellar, Star Trek StrangeNew Worlds), and for something kinda the size of a star, they are "scary."

In other instances (like in TV Foundation), a close orbit to the accretion disk is a source of suspense.

And then there's the "stealth" aspect. Stellar-mass ones and below are very small and (potentially) quiet for something with the mass of a star, eg easy to stumble upon.

And in some very advanced universes (eg the online Orion's Arm), even with "hard" sci fi, swimming through a star's nuclear plasma is totally doable. But a black hole is an impossible boundry of physics, and an particularly extreme object useful for astroengineering.