Yea I get that, but you can extend that logic to just about every domain of life. Should they be allowed to buy all their employees the best mattresses available because a good night's sleep helps productivity? Should they pay for a nanny because help with child care makes you more productive?

With that logic you could fund your employees entire lifestyle if you made the case that it helps them be more productive.

> Should they be allowed to buy all their employees the best mattresses available because a good night's sleep helps productivity?

Yes, potentially though it'd probably help to have data supporting that. But things like company housing or sleep pods can materially benefit the company (for one thing, if you can take a nap at work you'll work longer hours).

> Should they pay for a nanny because help with child care makes you more productive?

Sure, potentially. In fact, employer-provided childcare is a tax-free benefit.

Is it "customary" for a company to pay for mattresses? Maybe if the company runs an oil rig, but a tech company?

This even goes for things like salaries. If a company pays salaries that are way above the market rate, this could be seen as [corporate] tax fraud. But there often isn't a bright line in law, which is frustrating to us engineers who think deterministically.