The hand axe was ubiquitous before humans were even Homo Sapiens.
The hand axe, in quite specific form, was the tool of choice for more than a million years.
A million years. The pace of technological change was slow in a way that modern humans cannot understand.
Compared to the hand axe, domestic fire is a new development.
Homo Erectus apparently invented the hand-axe. H. Neanderthalis used it too, as did early Homo Sapiens.
But its purpose is a mystery.
It was not an axe. It did no heavy chopping. It might have served as a scraper, a digger, hide-skinner, occasionally a weapon.... But nobody knows.
Whatever its purposes, it was the tool the only one, for ages; or at least the only one in the archaeological record.
There came to be other stone tools, as we know. These new implements were part of a set that continued to include our handaxe for tens of millenia. Technological culture was profoundly conservative. The hand axe itself remained in production long after the invention of tools that were more sophisticated.
It may have also remained in production when it was no longer practical and diggings have found examples that appear ritual in function.
In truth, hand axes might have served a ritual purpose from the older times as well. Modern humans can only make abstract speculations based upon thin evidence.
It's kind of strange considering its importance that the purpose of the hand axe is not more clear.