I generally agree with you but I do find it useful to have some description of the state. If anything, I'd say Malatesta's definition is more relevant now than it was when he wrote it. At the very least when speaking to non-anarchists who may not have a grasp on how power functions. It points out specific areas of statehood that are broadly problematic and shifts the conversation towards the lack of political power and self determination present in our everyday lives. It's a useful rhetorical device, perhaps a bit dated, but most people aren't familiar with politics outside of electoralism. Having a short description on hand can help others towards radicalization.
Having negative terms isn't inherently a bad thing either. Every ideology has things they're for and against. Being able to clearly describe the things we're against is not only helpful, it's necessary. We use terms like domination, coercion and heirarchy almost exclusively in the negative, should we get rid of those as well?
It is a bit nerdy lol, but I feel the concept of a state still has relevance in our day to day work, even if onyl as a rhetorical device. It can, and still is, used to write good theory and analysis. At the end of the day, MLs and other authoritarians use the term positively and seek to grow state power. The state is still present in our everyday lives as I (and I think plenty of other anarchists) view it as part of the kyriarchy/mega machine/whatever you want to call it. What would you refer to this particular apparatus as?