Blizzard has explained changes happening to battle pet currency in Battle for Azeroth. New Polished Pet Charms will be used to purchase stones and other useful pet items.
The existing Legion pet charms, Shiny Pet Charm, can be used to buy existing unique things like vendor pets and toys in Battle for Azeroth. They can't be used for buying Battle-Training Stones, other pet consumables, or the Pocket Pet Portal.
The Pocket Pet Portal will cost the new type of pet charm, so you don't feel forced to do old World Quests for it.
If you have lots of Legion pet charms and nothing unique to spend them on, buy battle stones now since you can't in BFA!
These items are likely transferring over to the new currency Polished Pet Charm: Ultimate Battle-Training Stone, Mystery Bag, Flawless Battle-Training Stone, Big Pink Bow, "Dread Pirate" Costume, "Little Princess" Costume, "Dapper Gentleman" Costume, Marked Flawless Battle-Stone, Pet Treat, Lesser Pet Treat, Magical Mini-Treat, Battle Pet Bandage, Magical Pet Biscuit
You'll notice in today's new Beta update that battle pet currency has changed. Here are the main changes:
Pet Charms will be named Shiny Pet Charms. Shiny Pet Charms continue to be acquired by doing pre-BFA battle pet content.
A new currency has been added -- Polished Pet Charms. These are acquired by doing BFA content, such as Pet Battle World Quests.
Vendors that sell battle pet items that are always useful have had their wares changed to require new Polished Pet Charms as currency. For example, the vendor Serr’ah in Dalaran now want the new Polished Pet Charms. Similar vendors who sell such items have had their costs adjusted as well.
Vendors that sell things like unique pets or toys that have always required Shiny Pet Charms will still require Shiny Pet Charms. For example, Giada Goldleash in Dalaran will still sell all of her pets and toys for Shiny Pet Charms.
The Pocket Pet Portal item, which was an achievement reward for completing 30 of the Pet Battle World Quests on the Broken Isles, will be added to a vendor with a Polished Pet Charm cost. This is to avoid players feeling obligated to farm previous expansion’s world quests. You can do current content to catch yourself up. This is coming in a future Beta build.便携宠物传送门，作为完成30个破碎群岛宠物对战世界任务的成就奖励，现已可用抛光的宠物符咒购买。这能够避免玩家一次又一次完成旧的世界任务而感到厌倦。你可以通过新版本内容赶上这趟车。未来的某个beta版本将实装该改动。
Ultimate Battle-Training Stones are going to have their cost increased from 45 to 60 Pet Charms.
What this means for you: always-useful items will eventually move to the new currency, so you don't feel obligated to do older content. If you still need pets from older content, they are purchasable with that content's charms.
Spend those charms!
There will not be a conversion, nor will you lose them.