People who invest in or use BNB or other altcoins can not say they do it because of Binance or any exchange. They are responsible for their reasons of investment or choosing a coin for their transaction.
I do not go much further into knowing about the Binance Chain (BEP2) and most especially the Binance Smart Chain (BEP20). About using ERC20 network, it means you are sending the coin (which people thought is bitcoin but not, it is ERC20 token on ethereum blockchain) on ethereum network. On noncustododial wallet, such coins like renBTC and wBTC are example. They are not bitcoin, though the more people invest in it, the more the increase in bitcoin price, but because it is a token on ethereum blockchain, just like other tokens also, the more you invest on ERC20 tokens like renBTC, wBTC and others like DeFi tokens on ethereum blockchain, the more the price of ethereum is increasing. Also about BEP2 which is Binance chain and BEP20 which is Binance Smart Chain, all these chains are also used to make sure that as people are buying such tokens, the main chain coin which is BNB will be increasing in price. So as people are investigating on the tokens, the more the price of the main chain coin of the network is increasing. So, pooya87 is very right about this.
b. if the guide meant spending from own wallet. well then you come into the problems of not everyone only has one UTXO to spend. many have many UTXO's they need to combine when spending.
The transaction weight will increase but that is the reason why it is advisable to consolidate small inputs but while coin control can still be used to manually select inputs (do not get me wrong, I mean the UTXO) you want to use to make a transaction.
then insist the devs put in cleaner stuff that actually helps make bitcoin more useful day to day(on the bitcoin network), without all the stupid politics of making bitcoin far more worse to use daily just to promote other networks as things people should use instead
If you think you can not pay bitcoin transaction fee (which is low imo), then you can use the layer 2 solution which is lightning network. The mempool has been congested for over a year now, and if congested, there would be difficult adjustment on every 2016 blocks. Congested mempool also will still later become not congested again