Why depreciation is charged on fixed assets in profit and loss account?

'Asset depreciation serves many purposes, most of which include the recognition that time passage has a wear-and-tear effect on tangible goods, the reduced efficiency that ensues, and money a company must set aside to replace obsolescent equipment. Accounting regulations prescribe guidelines that financial managers must follow to report depreciation charges in a statement of profit and loss. '

A depreciation of an asset is pretty much same with an expense/loss if i may say, so it belongs to the P/L account to show the true net profit of each year. Depreciation is also shown in the balance sheet by reducing the value of an asset to reflect the true and fair value of that asset.