No, it isn't. It's way harder to deal with each employee than it is for the person to deal with their stuff as a contractor.
I'm going back to a full-time job in two weeks and the difficulty of managing stuff that individuals just shouldn't have to deal with is a large factor as to why.
In the real world? If you run a corporation, you are afforded, by society, extremely powerful and beneficial rights, and as part of the social contract you should be handling these sorts of affairs on behalf of the people who make you your money. It is mere decency, and "well employees should do it" without that automation that we both agree needs to exist--but, rather critically, tends to always be step two for certain folks, after "set them off on their ice floe", not step one--is morally super not great.
Because this is a process I'd do once a year (Or four times a year as a contractor?), I wouldn't remember what the hell I did last year, what software I was using, where I found the forms in question (Maybe they moved, maybe the government changed the rules, maybe the website that I learned all I know from is dead/out-of-date), etc.
A company's HR department/accountant does this all the time. This is their core competency. This is not my core competency.
This is the same thing as with self-checkout lines at the grocery. I've yet to see a single customer be half as efficient at scanning and bagging groceries as the clerks. Yet, it's cheaper for the store, because their customers' shopping time is 'free'.
[1] What changes when I'm on paternity leave? Unpaid time off due to sickness? This is something that most people do once, maybe twice in their lives. This is something that most HR people, working for businesses deal with all the time.
My small business doesn't have money for anything like that. It's me, the owner, doing it instead of doing my business.
Unless their personal time is worthless, it's functionally the same thing as lowering their wages, and contracting out to an accountant. Except that an accountant would probably do it faster and cheaper.
In another sub-thread, you said that this should be automated, and that nobody should have to do this busywork. I strongly agree. That's not the world we live in, though. As of today, somebody has to do this busywork - and when that somebody is an expert, they can probably do it a lot better then I can.