A catalogue is an asset you bought once and that earns less every year. The accounts have to say so.
A fund buys a catalogue for £1,000,000. The rights are real, the income is real, so the catalogue sits on the balance sheet as an intangible asset. But unlike a building, a catalogue fades: the songs earn most in the early years and taper as they age.
Amortisation is how the accounts admit that. It is the cost of the catalogue, spread across the years it earns, the catalogue equivalent of depreciation. Each year a slice of the £1,000,000 moves from the balance sheet into the as a charge.
The question this episode answers is not whether to amortise, a finite-life income asset must be amortised. It's on what pattern. And that single policy choice changes the shape of profit for years.