I’m on a ‘package’ with my vet so get wormers, flea treatment, consultations, claw clipping, ear hair removal, and annual injections as part of the package.
Worms cover a variety of types apart from intestinal ones, there are heart worms, lung worms etc. These latter especially cannot be controlled through ‘natural’ remedies however much we would like that to work.
Yes, there’s a risk with everything but that has to be weighed up versus the very real risks of other consequences.
Over the counter spot on treatments don’t work I agree. The ones you get from the vet might cost more but the should cover everything from worms (all bar tape worm) to fleas.
You get what you pay for.