Why would an average consumer prefer bitcoin over fiat options like credit card and ApplePay to buy coffee? Even assuming bitcoin transaction fee is minimal and instantaneous (say, after implementing Lightning Network), is the 2-3% transaction fee reduction worth paying with bitcoin, given its drawbacks such as volatility and lack of chargebacks?
There are billions of people that don't have access to credit cards and banking facilities that the privileged people take for granted. There are also people that get into financial trouble and lose all credibility in the banking system. Bitcoin provides a way for these people to transact without being part of the banking system. Coffee, however is a very superficial use case. One of the pressing needs is for people to send money back to their families in foreign countries, the current system of international payments makes it extremely expensive and very slow, Bitcoin and the lightning network can really help in cases like these.
Why would an average consumer prefer bitcoin over fiat options like credit card and ApplePay to buy coffee?
That's a meaningless comparison. Bitcoin (the blockchain technology) is not a payment system. It does not support chargebacks, it is slow, unreliable, inconvenient, and often expensive to interact with. It's the equivalent of trying to pay by putting bricks of gold in people's mailboxes.
It is however a natively digital, independent, and permissionless asset that can be transferred across the globe, free from censorship, inflation, or theft. Best of all, it achieves these properties without any trusted third parties that control the system.
In this regard, it competes with the dollar and other fiat currencies, not with credit cards. In fact, there is no reason why credit cards denominated in bitcoin (the currency) couldn't exist.
The hope however, is that due to being natively digital and permissionless, it is possible to build far better payment technology on top of this currency than what is possible with the dollar. One promising technology in this regard is the Lightning Network - a layer built on top of Bitcoin that offers cheap, fast, reliable payments which does not undermine the principles Bitcoin was designed for.
So why bother with the slow, expensive, and unreliable layer at the bottom, instead of directly building a payment system? Because different technologies are good for different use cases. In order to build a payment system, you first need something of value to pay with. The blockchain offers a way to do that, as it requires global consistency to guarantee no double spends are possible. But once you have that, there is no need for everyone in the world to know about your coffee - it can just be something between you and the seller.
Welcome sinoTrinity to bitcoin.SE! Your question is a bit opinion based, and not easily to answer with a yes" or "no". As this is not a discussion forum, maybe have a look at bitcointalk.org. They have discussed this up and down in many threads. My two cents:
If the fiat banking system is cited as example for coffee payment, then bitcoin might not make sense, due to limitations in imagination. If the mind set is structured in a way, that trust in fiat banking system (and all its disadvantages) is necessary, then there is no reason to switch.
However with a free, fresh, open and non-blocked spirit, new things come into mind, and can open the world to a whole new environment. Concerning the coffee: the bitcoin technology as per today might not be the optimum, hence the development into lighting. Maybe not relevant for a single coffee, but if you regularly get a coffee, then it starts to make sense.
There is tons of discussion on it in bitcointalk.org ...