In fact, this webpage has copyright residing in it. Who owns that – us, Greenwoods, as a firm, or the person who wrote this text? The default answer to that depends in part on whether our anonymous writer did so as an employee or as an outside contractor – and contract terms may override that default.
Of course, we are a law firm, not a music publisher, film studio, or publishing house – but this example just shows that copyright can become relevant to you even if you aren’t working in the sort of area you immediately think it’s relevant to. Copyright could reside in the user manual you provide with your product, for instance, or in the advertising copy you put out for promotional purposes. In some cases you would be fine with people copying your material – there’s no point issuing promotional material if nobody ends up seeing it! – but even then you’d want to exercise some control over how that material is propagated. Copyright can assist you there.