There was a time when the only available cheap flight was the Economy class. Nowadays, there is another economy class, called the Premium Economy. This is a reaction to the Economy carriers that have been growing their business in almost every part of the world.
Among other things, the Premium Economy, is a class between from Economy and Business. It does not have the fully reclining seat, for instance. But the extra legroom and semi-reclining space is loads better than Economy. There is also the convenience of sitting on a wider and larger seat. Of course, with wider seats, there would be fewer passengers for every row. There is also more legroom between rows.
In most cases, the Premium Economy has at least one meal, which is the same as that of the Business class, with the rest being the same as that of the Economy class. Passengers are also allowed more baggage space than Economy class.
The airline business is a cutthroat industry, and every airline tries to find an edge where they can get the passengers that they want, or they have the volume for a flight. The Premium Economy class gives passengers the option to upgrade without paying for Business class prices. The improvement is not just incremental, it is well worth the additional cost.
For long flights on a company expense account, the Premium Economy allows for work to be done on the plane. But for a tourist, the additional expense is better off spent on the ground or for hotel accommodations.