Emulators?

What are your views on emulators?

I know there are some pretty consistent attacks against emulation from companies out there and even questions of their legality circulating the media. Even Nintendo making it increasingly more difficult to be able to legally obtain the bios data for the Switch just to prevent "Piracy".

I believe Emulation is the future for media preservation, leading to less lost media over time so we can still enjoy the classics and learn from the dud for years to come. 

I am slowly trying to back up as much of my games library as I possibly can so that as my hardware becomes less usable, and my hard copies of software degrade I can still play through my favourite games.

What are your thoughts?

Any emulators of choice if you do use them?