It does solve a problem that exists. In fact the use cases are listed in the article: filing tax reports, opening/accessing bank accounts, etc. Basically the stuff where in the offline world you would've needed to show your ID.

However, many (all?) EU members already have developed their own national system. So this tries to unionize those systems so dealing with other member nations becomes easier. Today I often have to mail a bunch of documents if I want to prove my business ownership to foreign companies.