Having to do it at all is the hoop, and more than zero hoops is too many.
For sure, but it's a KYC for companies. How else would you expect B2B dealings and compliance to go through? They could do tax ids per country, but with DUNS, compared to local tax id, they get global ultimate beneficial owner as well as other insights. Getting a DUNS is free and relatively fast, unless you're in a hurry then there's a faster route that costs some relatively cheap amount. It's a common ID for global companies, especially those with international supply chains to rely on as "the id number" for companies.
Doing business is orthogonal to being a company, and depending on your country, some "company" forms are just VAT filing registrations for an individual itself with no independent legal status. What you normally call a company is something that behaves as an independent legal person.
However, it may be legally required to register a proper company if your yearly business volume exceed a certain value - check local rules - but it may also be perfectly fine to do business as an individual below that volume, in which case the legal entity is just you.
(The alternative to being a business in a transaction is being a consumer)
No, you didn't read that wrong. It does seem like intention is that individuals cannot publish (publish, not write) software for playstore if they cannot operate as a business; Individuals actually can operate as a business as a sole proprietorship aka soleprop which can and do have a DUNS number and is a legit way of doing business. Individuals without any sort of business entity attached to them do not get a DUNS number attached to them.
Doing business and registering a company (a separate legal person) are orthogonal concepts that are specific to local legislation. You can do business as a private individual, and various "company" forms in various countries are not actually companies but just VAT/financial registrations for the individual itself and have no legal status of its own. Whether you need to register a company form depends on local rules and may be subject to e.g. volume limits (e.g., okay below 10k USD annual).
The alternative to being s business in s transaction is being a consumer (as in B2C), and you're obviously not a consumer when publishing an app.
For sure, but it's a KYC for companies. How else would you expect B2B dealings and compliance to go through? They could do tax ids per country, but with DUNS, compared to local tax id, they get global ultimate beneficial owner as well as other insights. Getting a DUNS is free and relatively fast, unless you're in a hurry then there's a faster route that costs some relatively cheap amount. It's a common ID for global companies, especially those with international supply chains to rely on as "the id number" for companies.