Basically, users should be able to give each other silver and gold coins. 

I know you can "give" people silver by having them offer to sell you an item for that amount of silver, but that places the control in the hands of the receiver, not the giver. You can't give someone silver as a spontaneous gesture, and if the user is a new player, you may actually have to explain what they need to do for you to give them silver. 

Gold coins can't be transfered at all. I can only think of two possible reasons for this:

1. To prevent younger users from giving away actual money without realizing it,
2. Possibly to prevent people from abusing the referral reward

As to the first reason, I think that if the user's parent considers them responsible enough to buy them in-game currency, then they must also consider them responsible enough to manage it appropriately. Gold coins are valuable, and I think most users understand this.

As to the second reason, the only way I could see this as a possiblity is if a multi-accounter with multiple IP addresses were to funnel all the referral gold from multiple accounts into a single main account. Not only does this scenario seem unlikely, it would also be easily detected by the staff. 

Benefits of having transferable currency:

1. Facilitate off-site trades
2. Silver-to-gold exchange
3. Giving gifts to other players

I don't play many other pet sites, but I'm under the impression that most allow for currency exchange between users, and I'm curious as to why Beastkeeper does not. I recall reading threads from the beta phase in which most users seemed to assume that currency transfer would eventually be implemented, but somehow it never was. 

I'd appreciate any feedback on this idea. 

Yes, please!  A million times this, at least for the silver!  In my building giveaway, it is a constant irritation to transfer the silver that is part of it, because I have to tell people to sell me things, and sometimes coach them.

This could go bad fast. People will start asking for gold for their pets and items, then everyone will start to do it. Then people will only accept gold for their pets and items, and before you know it the game is run by people who can buy gold to get good pets and items. I used to play on a pet site that was like that, and it was horrible. Like being trapped behind a giant wall a hundred feet thick and all I had to get through it was a cheap plastic spoon.

I think it should be allowed for silver, but not gold. Even with the weekly charts to get gold.

@Monues I see your point, so how about enabling silver/gold exchanges but only BK itself is allowed to sell things for gold? (Custom skins being the only exception.) Or do you think the same problem would still occur.