Ask the average American worker if they'd like an extra $2300 a year. And yes I understand thats pre-tax. But even so, thats a non-negligible amount for a lot of people.
For whom $2,300 / year is meaningful is, dare I say, hard to answer question. Most of the people for whom an additional $2,300 / year is meaningful pay little to no taxes. However, a large chunk of these people also get Earning Income Credit. These people would lose at least part of this credit if their income increases. This question I believe can be answered by the bi-partisan U.S. Government Accountability Office or U.S Treasury- they certainly have the income returns for all Americans.
Stepped tax thresholds are always a problem when they incentivise low-earners to keep their income below a certain, arbitrary level. However, it would be inappropriate to deny employees a raise based on the existence of tax levels - after all, wouldn't the employees pay exactly no tax at all if they weren't paid? The tax is also guaranteed in most cases to improve the economy of the local area. I don't know the specifics of how it works in the USA, but I am aware of 'buy American' policies for federal public spending and equivalent rules for local government.
Say an employee effectively gets $10 less money, but the company effectively now pays the government $1000 in the same period. That might mean new bus subsidies, legal aid, development grants... things which make everyone slightly better off in the long-term. I think that's a good trade-off.
> For whom $2,300 / year is meaningful is, dare I say, hard to answer question
There were many articles written on the impact of the 2021 Advance Child Tax Credit (up to $1,800 per child over a 6 month period). The impact was very significant on lower-income families - which makes sense because for those earning less than $40,000 per year, that amount is more than the amount in one's paystub.
Glassdoor tells me the salaries of JPMorgan tellers ranges from $38,000 - $62,000 with a median of $42,000. So without digging into salary distribution at the entire company, I can yell you with certainty that it's a non-zero fraction.
In all those countries, average salary for JP Morgan employees is significantly higher (especially if you include expats). Also I think you are significantly off with Nigeria avg salary - no way it's so high in such a poor country.
Nigeria is tricky - I've seen estimates ranging from $130-$750. World Bank classifies it as a "lower middle income" country at this point, which would suggest they at least think the median is <$4k or so per year, I think.