Etherum settles in 12 seconds and can handle >30k transactions per second across it's layer 2s, by 2030 it aims to be capable of 10k tps on the main chain alone and enable protocol native shielded pools for private transactions.

Monero is already private and one of the most stable cryptos out there. It takes ~1 min for a single conf, but because there is no replace by fee feature, you can accept 0 conf tx for small payments.

Compared to fiat big cryptos like ₿, Ɱ, ETH tend to appreciate in value, so even if you were using them for payments without looking at the price, over a longer period, for most people the average they paid would be lower than if they used fiat, which only ever goes down in value.