Sui's fee-free transfer feature is pretty handy. Even if your account has no Sui, you can still make transfers using the Slush wallet. When I use other wallets on the Sui chain, I still have to pay transaction fees. As a payment infrastructure, there doesn’t seem to be any other public chain that allows transfers without any Gas fees in the wallet. Unfortunately, Sui has experienced several outages due to updates for this feature, and my wallet got hit by a BUG attack Sui is now fully unlocked, and the odds for a price range of $0.5–$0.9 are pretty high.