Because it's the only truly unique selling point of blockchain apps. So it has to be important to justify cryptocurrencies being valuable.
> I don't understand why this is seemingly considered a feature for all use cases.
Who says it's a feature for all use cases? It's a feature for some use cases. For those use cases, it's a major feature.
I can think of very few systems I'd want to use where nothing can be deleted.
I don't understand why this is seemingly considered a feature for all use cases.