> Biggest mistake most librefication projects make is to do their project out in the open

That's not it. Most youtube downloaders are not developed in the open and Youtube still breaks them every other week by changing on purpose the way they operate. And, unlike highly obfuscated instructions, studying the network queries used by a simple app does not require expensive reverse engineering efforts from Spotify engineers; essentially, it's the same as developing in the open.

The only case i can think where obfuscation might help would be if the actual Spotify API consumers were servers by the app developers (or some form of obfuscation via residential proxies) and the app developed an entirely different API to/from its servers. But then, you're back to the developers and hosts can receive legal threats, etc...