Each battle that you win will yield experience for each pet that participated. However, deceased companions will not receive any experience (so make an effort to keep them alive by swaping in a different pet). Experience gains are based on your pet's level compared to the wild pet. Defeating a higher level opponent will grant more experience than a much lower level one, but be ready for a tough fight!
I have tried it a few times. It's good if you're new to the game. Otherwise not so much. I found I leveled slower by using it, as it's suggesting to take the longest possible route usually. Basically following roads everytime, when you could take an easy shortcut. Especially if the shortcut involves a bit of fall damage, it's out of question. The "go here" spots don't also update if you take a shortcut, and then the waypoint arrow points to wrong direction. But perhaps it has been updated since then.
For example, the Azure Whelpling belongs to the Dragonkin family. However, it has Beast, Magic, and Elemental abilities in addition to a Dragonkin attack. Different attacks are strong and weak against different family types. Having a diverse spell selection might increase your chances of being prepared with a strong attack against an opposing team.
Extract ConsolePort to Interface/Addons. The addon can be downloaded through the Twitch app too. Make sure the addon is enabled when you log in to the game. Install WoWMapper and connect the controller to your PC via cable or bluetooth. Make sure the controller is recognized by your operating system. Log in to the game and make sure ConsolePort is enabled. Now it's time to choose your controller layout. Grats, you can now start playing the game with a controller. (Optional) Enable Action Camera for extra immersion by typing /console ActionCam full, /console ActionCam basic or /console ActionCam default, depending on whichever you prefer most. You can turn it off by typing /console ActionCam off command.