Name and date makes it much more difficult for someone to "swap" you stone with their inferior one as well. Good tools are a large investment. Conductor's watches for the railroad cost upwards of a month's salary for instance, and the railroads quickly discovered that the only way to keep the watches in good condition and on time was to require the conductors to purchase them and pay to maintain them.
Works the same way for tools.
And people on the lookout to "acquire" other people's better stuff fraudulently were as common then as they are now....
I think there is a line from a song which sums this up very well, 'You never learn to fish on a borrowed line'
I was on the board of a local college for apprentices, engineering and construction skills mainly. The students had there own cafeteria/restaurant which needed decorating every year and was in a mess part way through with graffiti and food. we hit on the bright idea of taking ownership and the construction students had the first job of the year as painting the cafeteria in whatever colour they wished.
They took ownership and the walls stayed immaculate for the 12 months.
Must admit that some of the Japanese stones with markings are bordering on works of art, I would be tempted to have them on display!