Yes! There's a strong tendency toward measuring unvalidated proxies because they are easy or convenient to measure, without even constructing a hypothesis about how these proxies relate to more important things, much less testing it.
Measuring productivity has to start with what matters: do your end-users (these are not necessarily your customers) like what you do? And often it is hard to get this information. Just asking them will lead to biased responses, but there are ways to deal with that.
I happen to be in a business (let's call it food) where I can observe the end user using more of their money with our customers rather than their competitors when we do things right. That's a strong signal -- probably stronger than asking them -- so a very fortunate starting point. (Of course, there are still confounding terms like seasonality, economy etc to grapple with, but there are ways to deal with that too.)
Starting with that one measurement that matters, one can begin exploring proxies. Set up a hypothesis: "Velocity would be easier to measure and the number would be available faster. Does it correlate with our one good metric?" And then you run the experiment. It might take weeks or months to get back the end-user-happiness data that corresponds to this week's velocity, so these tests are expensive (but pay off many times over when you find good proxies.
In the end, you should be able to construct a somewhat sensible model of user happiness, and answer questions like, "if we hire another team member and therefore increase velocity by 3 %, how much happier will our users be? And what is that worth in sales?"
When you can convert everything to the same unit of measurement (dollars are an easily explained option, but log-dollars are a personal favourite of mine) you get intense clarity and alignment around priorities and decisions.
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All of that said, development speed, as defined in the Accelerate study in particular, is one of those generally good things you pretty much unconditionally want. The reason is given in the study and expanded on further in Reinertsen's Principles of Product Development.
The reason speed is important is that successful product development is controlled by surprises. You will discover something tomorrow that will make you wish you had prioritised differently today, and being able to pivot quickly on surprises is how you both de-fang the biggest risks, but also how you throw yourself at opportunities before your competition even realises there is one.