They are just covering themselves. No chances of lawsuits if they advise against.
I’m 99% sure my 2005 NB would be fine, but there’s only 4p/litre difference at Tesco here in Bournemouth, and I’m definitely getting better mileage with E5 so it’s not a direct comparison. Two quid extra for a tankful. Also, it might be confirmation bias, but the car seems to be a bit more willing up through the gears when I put my foot down.
It’s the job of any business to maximise profits. It’s the job of government to make sure there’s no cheating. I was amused by an Extinction Rebellion-favouring friend complaining about the rising cost of fuel: surely that was what he wanted