I'm not sure what stage of company we're talking about here.
I'd argue that for ALL companies, in any industry, working capital--measured on the balance sheet--is a critical data point. That is, you may be booking revenue but not collecting cash from your customers (in an extreme case, the "revenue" may be fictitious, if the software doesn't work and the customer refuses to pay). And while you might have $x of cash on the balance sheet, you could also have a huge and looming payables balance because you're waiting to pay your bills until you're N days past due.
Also, revenue is just what you can actually book per the accounting standards, which has lots of specific tests for software companies. For most SaaS companies, a key number is also deferred revenue, a balance sheet item that records the difference between the cash you've collected (say, up-front for 12 months) and the remaining performance obligation to deliver software over the period. Or, if you have a big service component as part of your offering, a number to watch is the amount of revenue you've booked but not yet billed.
As an investor, I'd also be curious about the future obligations of the company that will consume cash, such as big leases, debt, and other liabilities (eg, legal judgements against the company).
Investors are free to ignore whatever information they'd like, I suppose. And a tiny two-person company probably has a very simple set of financial statements, if any. But those two founders have the ambition to build a big and successful company, I'd argue that understanding how to read financial statements with some mild degree of fluency just isn't that hard and is a very useful skill.