It's just different forms of shareholder assets being traded for other assets, by the shareholders (or rather, their majority vote).
In the current example if the cash is coming from a debt instrument is it not bank funding it now?
it is typically about who is fronting the money now, it could be your bank making loans, or from cash reserves you have, fresh stock issue, selling another asset, or even the target's bank as in the case of LBO.
The shareholders always end up paying for it eventually in some form or other. Differentiating it by the current source helps understand the deal structure and risks better.
When doing a deal, it comes down to price and source of funds. Changing either can drastically change how good or bad the deal is.
Cash paid in this instance is treated no different than cash in their normal operating expenses. If either generates profits in line with their current expected returns, the stock price stays the same, and everyone is indifferent to the transaction.
Same goes for stock issuance. If the expectation of the use of proceeds from the issuance are in line with the company's current expected returns, everyone is indifferent.
Your statement is still true, and the stock market jumped today on the news, so I feel my connotation is misplaced.
This is a pretty naive depiction of Wall Street.
The $12B comes from Nvidia the company, the remaining money comes from Nvidia's shareholders directly.
[1] Only if the valuation of ARM is "worth it" the fresh issue of shares will not cost the current shareholders anything. This is rarely the case , if Nvida overvalued(or less likely undervalued) the deal then current shareholders are giving more than they got for it.