Okay, that's fair, I've heard that before and forgotten. It's true for some older cats or cats with poor teeth who cannot manage their claws themselves (younger ones manage them perfectly fine by chewing them as part of their grooming process, and scratching) then I accept that trimming may be helpful but in most cases you should leave your cat's claws alone.
Likewise an extreme case like Contrary's (I wonder if mittens would have worked here too, but the cat was obviously suffering) but for ordinary pet owners - no. Use a citrus spray or onion on your furniture to dissuade them. It's not about rejecting new products out of hand - there are lots of new products for cats which I think are a great idea, but anything which directly affects how the cat is able to use their body should be treated with a high amount of scepticism in my book - it needs to be proven that there's a significant benefit, rather than using something until you have significant evidence of harm.
To me it's like getting a puppy but saying oh I can't be bothered to deal with their biting stage and anyway dogs can really hurt people so let's just remove all their teeth - it would be so cruel and unnecessary. Pets aren't just fluffy fun things, they do come with responsibility and inconvenient parts too. Anybody who's trying to sell you a perfect solution to any of these inconvenient parts should be viewed with extreme suspicion, because it's rarely that simple and problem free.
Spraying and heat are not really the behaviours you're eliminating by neutering a cat, the point of neutering is to prevent them from reproducing, which is a different issue entirely.