We have Petplan for our four pets, have had it for them all since they were 8 weeks old. We've claimed around $15k for the dogs over the last four years. They are accident prone. Yet to claim for the cats. Never had Petplan knock back a claim yet although they do take awhile to pay us back. They can pay the vet directly but that would need to be worked out with your individual vet, not all practices would accept that.
It's absolutely worthwhile.