Ideally you have a little in the way of things to protect your goblins so you can actually use them given all the effort needed to have them work
That's only for drawing cards, though
And if that's the way he wants to have fun with it, then that's perfectly okay."
They are mechanically identical to their non-serialized counterparts
In reality, our deck is mostly Cats (although we do have a few Dogs as well), but the power of Rin and Seri, Inseparable is that every time we cast a Cat, we get a 1/1 Dog token, which then turns into removal with Rin and Seri, Inseparable's activated ability
Explorer is one clear example of a game mode in which players are asking (or, well, yelling may be a more accurate term, although some are resorting to humor) for more cards there's even a Support Ticket on the topic, with a lot of upvotes