That kind of comparison just completely ignores opportunity costs, so it will result in mistakes any time they are significant.
Making the comparison is not the last step before decision. The comparison itself ignores opportunity costs, but it doesn’t keep you from going on to perform an opportunity-cost check. The output of the comparison can then be combined with the output of the opportunity-cost check to determine a decision.
That kind of comparison just completely ignores opportunity costs, so it will result in mistakes any time they are significant.
Making the comparison is not the last step before decision. The comparison itself ignores opportunity costs, but it doesn’t keep you from going on to perform an opportunity-cost check. The output of the comparison can then be combined with the output of the opportunity-cost check to determine a decision.