[hyperrail]

Fringe benefits not specifically excepted are also taxable wage income in the United States, but I don't think employers are forced to gross them up at the highest marginal tax rate or are otherwise discouraged from giving them out in lieu of cash.

The USA's income tax agency, the Internal Revenue Service or IRS, has a whole booklet to help employers figure out how to withhold taxes for fringe benefits:

https://irs.gov/pub15b - Publication 15-B, Employer's Tax Guide to Fringe Benefits

It discusses the de minimis exception mentioned in the originally linked page, as well as exceptions for some meals - important if your employer gives you free or discounted cafeteria lunch or restaurant lunch discount coupons.