Snacks can be trivially gamed as well. The primary difference is that snacks aren’t a widely accepted metric, which is why they might be a good one; that is, once a metric is established, it ceases to be a good metric.
Snacks and other small perks are trivially gamed. There is a decent argument that companies that spend money on frivolous benefits to project an image of strength have something to hide. Often the frugal, conservative companies that count the pennies lead to more stability and long-term strength.