Almost all tokens running on etherscan are also on bscscan, since bsc is a product of Etherscan even you can use a single address for both ETH and Binance smartchains, I'm not sure if bscsan adoption can overthrow ETH in the future.
not only BSC we can use in ERC address. most other network smart contracts you can also use via an ERC address. all settings can be customized in metamask.
By far the biggest popularity and adoption is still for ethereum. not so good for BSC if later more and more are just scam projects.