what I don't understand is the term "unexpected bill"
^plumber
boiler
electrician
Dentist (other than check up)
private physio/osteopath if the NHS have discharged you and you still struggle to work
Car repairs
Roof repairs
list goes on^
But most of those aren't 'unexpected' only irregular.
If you have a house, car, pet, teeth etc, they will need money spending on them sooner or later to repair or replace as necessary. Hence why it is a good idea to put money by to pay for it when it does happen. Same for Christmas, holidays, insurance, weddings, funerals, etc.
Just because the money isn't taken out of your bank account by direct debit, doesn't mean you won't have to pay it out sooner or later.
Nearly all the people in the article would have money spare for this sort of thing if they hadn't already spent it on smartphones and haircuts.