I agree - the title of this article should have been 'The Importance Of Choosing Realistic Data Types When Designing Your Schema'.  I'd seriously consider 're-allocating' whoever designed the table with 'int' in the first place as they clearly have no idea about the business.

The best designers/DBAs are ones that fundamentally understand what their company's business is all about because it means that they will intrinsically factor that knowledge into every stage of the design process. 

Identity columns are simply an efficient way of generating unique keys and I'm a little tired of seeing them demonized when the real issues lie elsewhere.