Do horror movies serve any purpose?

Seriously, I was watching this Japanese horror flick called Grudge
something (with English sub-titles, of course). Admittedly, it had
it's moments of suspense and gore...but in the end it all seemed so
meaningless that I was kind of disgusted!

Is there any joy in watching 'em...that I failed to extract?

Thanks, for helping out :)
Now, disgust and disappointment can't be entertaining!!!