FWIW, employers that provide free lunch do so partly because of the tax efficiency. The IRS allows certain perks to be provided on-site "for the convenience of the employer". This argument would not apply for at-home workers, so the stipend would have to be included in the employee's income. Not a dealbreaker, but it does affect the calculus.

Who is doing this? I've not heard of most companies doing anything about lunch for WFH employees.

As usual, depends on location. In France employers bigger than some numbers are mandated to provide some lunch allowance in specific vouchers/cards usable for grocery shopping/restaurants/etc. OR at least a partially covered cantine.

There's no specific provision for WFH, so we still get lunch allowance ( 9.80€/day, iirc the minimum is around 6.50), which is a bit hard to use when you no longer go to a restaurant every day.

I used to work in PE (private equity), very common there.

One daily DoorDash lunch order, put anything you want.