Apart from the slow confirmation times and the low TPS issues - for any average consumer what is the benefit of making an irreversible payment?
Benefit from an irreversible payment? Very little, however there are other benefits to the customer, primarily (current) low cost of use and the ability to send money instantly (yes, I would argue that bitcoin transactions are for all intensive purposes instant from the viewpoint of the customer, regardless of confirmation time)
Credit cards are costless to us and send money instantly as well. It's fairly obvious Bitcoin doesn't compete and certainly does not offer a superior product on these grounds.
People would use Bitcoin to to pay for something online because of the lower cost. To counter the fact that payments cannot be reversed, consumers should only deal with companies that have a sufficient reputation that they can trust items will get delivered, for example if an Amazon order does not get delivered, I would think that the majority of the time Amazon can resolve this issue prior to the customer ever contacting their credit card company (yes this will lead to more centralization, and yes this will make it more difficult for newcomers to enter the market online).
Consumers can also use Bitcoin in person in similar ways that they use cash in person. If someone were to trust a mom and pop store to hand them $500 for a TV, then there is really no reason why they would not trust them with $500 worth of Bitcoin for the same TV. Such store could probably even offer a discount for paying with Bitcoin over cash because of the lower costs associated with protecting bitcoin over cash.
It seems you pretty much confirm CIYAM's point which is that there is little incentive for the consumer