General Electric recently invested $500,000 in purchasing new machinery crucial for its manufacturing operations. The machinery is projected to have a useful life of 5 years and a salvage value of $50,000. In light of this investment, provide a comprehensive explanation, detailing step-by-step how General Electric should calculate the depreciation expense for each year using the straight-line method. Additionally, discuss the significance of depreciation in reflecting the true cost of asset usage and its implications for the company's financial statements and tax obligations.