> compared to the existing banking system it's trying to replace
I don't think it's appropriate to compare it to the existing banking system (whose featureset goes far beyond payments and managing account balances).
It's appropriate to compare it to existing payment and account systems. And on that front, compared to e.g. Mastercard, there's no way Bitcoin is more efficient. TXs/watt, $/watt, however you want to measure it.
Also, it should be obvious that sources from the cryptocurrency industry have a conflict of interest. If there are better sources than something like Binance, then those should be used. If there aren't better sources, well...
Lightning isn't Bitcoin. It's an L2. It helps implement actual practical payments for Bitcoin, and doesn't (afaiu) manage account balances. In other words, you cannot seriously compare it to Mastercard; you've gotta include Bitcoin itself.
I don't think it's appropriate to compare it to the existing banking system (whose featureset goes far beyond payments and managing account balances).
It's appropriate to compare it to existing payment and account systems. And on that front, compared to e.g. Mastercard, there's no way Bitcoin is more efficient. TXs/watt, $/watt, however you want to measure it.