Because you have to realize over 85% of cryptocurrency transactions on all the major blockchains according to some data i read about a year ago are worth less than $100 USD.

That means most people are moving small enough amounts for whatever reasons to be able to use lightning and integrate it into their lives. Also, lightning has value because it's essentially feeless, instantly available in the receivers wallet (assuming there are no routing delays), and is super conveinient given everyone is already glued to their smartphones most of the time anyway. It's actually easier than having to pull out a debit/credit card and swipe it in my opinion.

Lightning is the only way bitcoin stays relevant and doesn't eventually die in my opinion. It's the only way for bitcoin to become a widely accepted method of transacting funds/paying for purchases/services.

As stated, the majority of the earth's population doesnt have the time, patience, or extra funds (even 50 cents or less is a turn off to people when they can pay another way for free) to deal with on chain bitcoin transactions.