https://en.wikipedia.org/wiki/Libor#LIBOR_cessation_and_alte...
With a finite maturity, you invest (let's say) $2 million, earn your yield for 5 years (let's say LIBOR + 7%) and then you get your $2 million back and you can decide then how to best re-invest your money at that time given the situation. There is a reinvestment risk here, where after 5 years you might not be able to find similarly attractive investments but unless you an insurance company or a pension fund trying to meet very specific long-term obligations you don't really need to worry about super long-term reinvestment risk. On the flip side, if you get your money back after 5 years you might be able to find an even better investment, and that kind of optionality is very valuable.
You have an 80% chance of getting your money back with BBs.
Also, I didn't read the specs on the Listerine contract, but I assume that if they raise the price of Listerine, then royalties scale with it. While in short term consumer staple prices are sticky, they scale with inflation over the long haul.