I believe that these types of rules are intended to discourage frivolous expenditure but inevitably indicate weak management lower down (perhaps the CEO is a micromanager). Unfortunately, they discourage all expenditure, even that which is obviously desirable, as in this case.
IMO, any policy which involves approval of senior management needs to be seriously thought through, as it gives an impression of how the company is run to competitors, customers, suppliers as well as employees.
Many years ago I worked at a company which instituted similar rules from time to time, possibly because it had grown faster than snr management could cope with. This company is no longer around.