What I am thinking too, also just because of what you stated already, it will also help the mempool to be less congested as some people will be able to pump the feenans increase the chance for the unconfirmed transaction'to be included into a block.

But that is not what o_e_l_e_o is asking. Even if 90% nodes signal for it, there will be a time at the start that just less than 50% nodes will signal for it and the number of nodes that will be signalling it will be increasing. If it is 50% to 50% of the nodes that signal and that do not signal, that it is possible some transactions in the mempool of the signal nodes to flag the transaction as RBF while those that did not signal will have the transaction as non RBF. So which one will be included into a block and be confirmed?

Yes, just like https://www.blockchain.com/explorer?view=btc do exclude it while some do include it. The thing is it is possible an unconfirmed transaction which is non RBF will be flagged as RBF on some mempool (mempool of the nodes that have signalled for it already) and remain not flagged as RBF on some other mempool (mempool of the nodes that have not signalled for it).

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I guess this might have not been proposed if many SPV wallets support RBF transaction by default like on Electrum wallet, but most of them just failed to be up to standard, but people just prefer to use those inferior wallets because they are ignorant of it. I know this will be a good implementation but I did not know how it is going to work fully yet, maybe those wallets will have not option than to support it, but if they do not still support users to be able to pump fee, this will encourage the users to import their seed phrase on wallets like Electrum and use Electrum to pump the fee.