Forget tax credit, as it doesn't have to be a credit which is typically a 100% reduction in taxes. Deductions offset profits and reduce taxes in proportion to the tax rate, or even dropping overall taxes to a lower bracket. Most business reviews their tax liability in the final quarter and decide if should have capital expenditures in the current tax year or defer to the next tax year. Yes, I can understand your second part "would be much better off spending it on an enterprise vms or better cameras" but that is a judgment call, product A vs product B and personally see the advantage of minimizing the computer cost to accommodate the other equipment - but that is not our call. My point is that tax planning throws the economics off where an 'overpriced' computer (or whatever) may serve it's purpose for expenditure that others would not consider.
To illustrate, while I would have liked a Sony A9 camera body ($4500) and could rationalize it's use, two days ago I bought (true statement) another Sony A7rII camera body ($2700), and hypothetically lets say you liked that camera too and bought one. In your case, you are out the $2700 (plus more for a lens) and it has no impact on your taxes despite the fact that you used your hard earned money to purchase it. In my case, it reduced my hard earned net taxable business income by $2700 which at the 30% tax bracket (I wish) would have an effective cost of $1890 as it reduced my taxes $810. Now if I truly had profits that pushed me into the 30% bracket, that A9 would be sitting on my desk - but that is my call, not anyone elses. The additional body is not just a tax deduction but also makes solid business sense as well, besides qualifying me for Sony Pro support, it enables me to increase future business income by hiring a second shooter for a wedding or corporate event shoots and not increase post processing workload as color balance between the two cameras would match. The A7rII is a phenomenal camera and we could argue if should go the original A7 (now $900) or the recently introduced A9 or the two cameras in between, A7II A7sII. Belive me, those senarios went through my head. But ultimately, it was may call for the second A7rII to join my camera portfolio which also includes the A6000.
