Pros:

Once a snake learns that it is food, he or she will gobble it down like Pac-Man.

It's relatively inexpensive.

Apart from issues with heavy metals ("EXCELLENT!" *GUITAR ARPEGGIO!*) and parasites - both of which are issues with just about any fish - it's pretty safe.

No thiaminase.

Humans can eat it too.

And, if you get it frozen, you can probably keep a large portion of it on hand for not a lot of money.

Cons:

As with any fish, be wary of where it comes from and what risks there are.

Parasites can be an issue, but freezing the fish for an extended period of time will kill them. Cooking the fish - which your snake may or may not like - can help with that as well.

If you get filets, there are no bones, so you will have to supplement the diet with other items - like whole pinkies - or calcium powder. Or ground-up bones.

Some snakes won't take to fish filets, because in the wild, they are used to live prey; but garters can be trained to eat it with patience.

About half of Little Dude's diet is tilapia. The other half is nightcrawlers. So far, I have only seen Tiny eat nightcrawler pieces.