I can agree that LLMs might yield better results overall than a standard spellchecker.
If your goal is to check your writing for plausibility and rough grammatical correctness, that's certainly an open problem for deterministic, conventionally-written software tools.
My goal with spell checking is to make sure my occasional mechanical typos while using a desktop computer get caught before someone else has the chance to be annoyed by them.
I don't have an issue with using the wrong word entirely when writing at a computer, so that's not a use case I think about. It does happen when I use a smartphone, due to autocorrect and predictive typing, but that's not a case this Claude skill applies to.
So, for my use case, the ~6 orders of magnitude more energy used to send documents over the network to be hyperchurned on an array of GPUs guzzling electricity is pure waste.
It also makes the whole process orders of magnitude _slower_.
I find that massive waste and slowdown infuriating, even while conceding that it can perhaps deliver a little more value then the deterministic spell-checking algorithms I rely on.