The company isn’t using the travel miles. You’re basically saying, “I’ll take away a small perk from people who are forced to travel.” It’s not like they’re stealing from the company, the company sent them somewhere else and they just got a tiny bonus for it.

The proper thing to so is stop those managers who travel too much.

The issue is that it creates an incentive to maximize the cost of travel as the employee directly get miles based on the price.

I see this all the time with employees/managers booking a 1000$ flight that will give them 10k miles instead of a perfectly fine 400$ flight that would only give them 4k miles.