As U.S companies write down more of their assets during the coronavirus pandemic than they have in years when performance is handicapped, there are concerns about companies taking 'big baths', (that is, to manipulate the income statement for a one-time impairment to make future results look better).

Some suggest that companies should just depreciate/amortize their assets according to a prescribed schedule.

What are the advantages of requiring companies to depreciate or amortize assets according to a prescribed schedule?