I have a hard disagree here. Though, I suspect it is a matter of what your code is doing.

First, my objection, though. Pushing this "to the users" is in no way easier to support. It is easier to abandon, but support is a different thing. You will have support contacts. And, due to the distributed nature of the deployment, you will have a much harder time isolating your code from the environment it is in.

With a service, it would be a lie to claim this is easier, but it is a bit more approachable.

Now, a difference, I believe, really comes in to whether or not there is state associated with what you do. If there is, and it is not something that makes sense to move close to the user, then a service is pretty much required. If there is no state, make sure that is not artificially done by just moving to all state being managed by the user.