No, there is no good reason for it. It's just always been that way. Well, since they had clockwork systems to ring them, maybe since the 19th century? I doubt they used to stay up all night just to ring the bells.
But it's oddly reassuring and distinctive. It tells the town that life is plodding along, in blocks of fifteen minutes, the same way it 'always' has. And if it stopped, people would notice. And ask themselves the question: why? For whose benefit? In French rural villages there's a phenomenon of newcomers from the city, in search of 'idyllic country life' complaining about cow bells and cockerels. You couldn't make it up, and you don't have to.
Should the bells be stopped because the locals decide 'actually, we don't want this anymore'? Absolutely. Because entitled owners moan on Instagram and Tripadvisor and write to the council? I'd say 'no'.