All the risks that Ethereum has SmartBCH will also have because SmartBCH is pretty much a clone of Ethereum; the only difference is that it uses BCH as its primary token, which on the sidechain will be equal to 1 to 1. Not only could you risk protocol failure, but also scams and useless tokens. Hopefully, we will not see another ICO fiasco because the community will be on alert, or I hope that the community does.
I think you should read the following article if you need to know more about the risks that SmartBCH could bring and if nothing more, so that you learn some of the terms that ETH users use because they will apply for SmartBCH since the sidechain is pretty much a clone. What runs on ETH can now run on BCH, and not only the good projects but also the bad ones.
https://ethereumprice.org/guides/article/yield-farming/
CeFi allows users to borrow stablecoins and other assets and put cryptocurrencies as collateral, making a secured loan with your crypto. That is what you should be able to do with DeFi; you should be able to borrow against your holdings some stablecoin so that you can buy either other or your initial asset. If you have Bitcoin Cash, you should be looking at getting more Bitcoin Cash or something similar. CeFi, the risk is that your custodian goes bankrupt. With DeFi, you risk your preferred stable coin losing its peg either because the third party that emits it goes bankrupt, something goes wrong with the protocol, Smart Contract, or an attack by a hacker.
Using your Bitcoin Cash to buy an unknown token yet so that you can stake or farm it is just asking for trouble, and by that, I mean the loss of your initial capital. Many of the tokens that run on ETH are just speculation assets that allow users to farm for more of that same token. Still, if the token comes down in value, the yield that you are farming won't be enough to cover your losses. The rug pulls a reality on DeFi, and SmartBCH won't be any different.
The latest risk is that your preferred DeFi networks get centralized, and a government can apply sanctions to it like the government will be able to do with Ethereum once it goes proof of stake. And I will watch out for SmartBCH in this regard, too, because Sha-Gate v2 is talking about using proof of stake to validate blocks, which is the same mistake ETH is making. The bridge between SmartBCH and Bitcoin Cash is centralized at the moment. If Sha-Gate V2 could introduce stake concentration risks, I recommend you don't invest in I unless you are okay with governments dictating how you can use the network.
I am trying to say to be careful with SmartBCH DeFi because it will bring opportunities. Still, it will also make many people lose their satoshis to people who know better than them, know what they are doing, and have an advantage over regular holders. Be careful with BenSwap if you are going to farm because if the value of the token you are going to farm comes down, you will lose your initial investment. And I am saying be careful because, on their farming page, they are showing an 800% yield, but they don't tell what the risks are.