The idea is that you're converting some % of developers' salaries into intellectual property (i.e. code), and that intellectual property is a capital asset that depreciates over time in the same way that a tractor or a widget-making machine would.

The salary is not the asset, it's an expense that produces an asset.

Ah, that makes sense now. The value of the code itself as an asset would be really subjective, but what you pay someone to write it isn't. Thanks :)

The reason amortization exists is to reduce taxes in later years:

If a company invests $1 million into an asset that earns $250k each year over 5 years, the company would otherwise see a $750k loss the first year followed by $250k profit for 4 years. By following an amortization schedule, they are taxed on a steady $50k profit each year. In other words, the taxable effect of the expense is "spread" through the years in which that asset is expected to earn income.