BUSD and USDT are stablecoins that both have their own advantages and disadvantages, USDT is a coin that is managed on the Ethereum blockchain, whereas BUSD uses the binance network as a place to operate, and I think both have very capable technology, so both are great and safe to transact.
I personally like Binance stablecoin more than tether dollar because Binance do audits and things are more transparent while tether is just a little bit shady and never heard if they do public audits and things like that.
Usdt is a risky not pegged shitcoin. The only reason it is used a lot is because it was the first anc for dome strange reason people keep using it. There is to much smoke there that there must be a fire.
I am not a huge fan either but the same logic applies with Bitcoin. There are many projects and coins that provide more use cases than BTC but because it was the first one, it still has the biggest market cap. Similarly, no matter how many flaws are there in tether, it still remains the top stablecoin.
Also Tether is much more expensive in transactions. Withdrawing USDT from exchanges is painful, but BUSD is quick and cheap. The point with the audits is a good and important one. Nobody knows what's going on with Tether.
As for Bitcoin you should keep in mind that it is not worth the most because it was the first, it is worth the most because it is the most secure blockchain in terms of hash rate. Price and hash rate are strongly positively correlated, you can check the data.