Wow. This card is...pretty bad.
On the surface, it seems pretty straightforward. You get one Magnum Opus click each turn; that's pretty good, right? Two credits for a click is about as good as you can get normally.
But it's actually far worse. Because unlike Mopus, you are obligated to use it every turn, whether you need it or not, and you can't use it more than once per turn. Meaning that, on any given turn, you're either going to be starved for credits, starved for clicks, or both, and you won't have the versatility you need to deal with that. With Mopus, you can spam it when you need the money and ignore it when you don't.
Now, by itself, this wouldn't be a total dealbreaker. In my games with a Tri-maf Contact I typically end up using her once per turn, and it would be nice to not worry so much about tags.
But the install cost of Hard at Work is just so prohibitive. 5 is a huge tempo hit, and Hard at Work doesn't really pay itself off until 5 turns later, and that's being generous.
You might point out that with Aesop's Pawnshop the downsides of this card become less severe, which is true, but you would still be selling Hard at Work at a loss, meaning that you would have to leave it up for a few turns to try to recover that loss, and are still operating at a substantial deficit in those turns.
Ultimately, almost any deck that is running this card would be better off running basically any other economy card. Daily Casts is cheaper to install, doesn't steal your clicks, and destroys itself when you don't need it anymore, giving you the clicks you need to either run or draw to find another one. Liberated Account costs one more to install than Hard At Work, but pays for itself almost immediately. Armitage Codebusting is dirt cheap to install, and gives you six 2-for-1 clicks as soon or as late as you need them. Out of faction, the aforementioned Tri-maf Contact gives you the 2-for-1 click each turn for a much cheaper install cost. Professional Contacts has the same install cost and helps support a healthy economy. And if you can swing the memory, Magnum Opus is better in every way.