Clinker: Vertical joints without mortar - Is that okay?

now don’t be so loud, bricklayers are not precision mechanics, but since the [Klinker] still need to be grouted, the vertical joints will also be closed and sealed.

But the photo shows it hasn’t been grouted yet?

To me it looks like the step of bringing the joints to the same depth (I wouldn’t call it smoothing here) has already been done, and only in those butt joints that are narrower than the tool of the person adjusting the aesthetics has it ended with a rather unsatisfactory result.

Bricklayers are not precision mechanics,

... but still seem to work with a more appealing result. Exposed masonry requires skilled bricklayers; here it seems to me someone was at work who might be a quite remarkably talented horse groomer for a trained baker. The contractor apparently misunderstood the client’s wish that it should not look sterile to mean that unskilled labor could be used.

if a management consultant can assess that, well... I hope you don't have any bricklayers working for you..

The overconfidence, which according to common opinion is an essential prerequisite for my profession, does not even need to be applied in this case: my late grandmother would have put her word and seal on it without glasses that the photo is not the work of a trained bricklayer. Such a person could certainly work in the same way, but would only allow that on a wall to be plastered. Even a management consultant would not complain about that - but a visible masonry surface is, in my opinion, rightfully expected to be done with more care. But I gladly admit that I can only judge that, and not demonstrate it better myself.

I am of the opinion that the butt joint according to DIN EN 1996-2 has a guideline dimension of 10 mm. This also enables "man" to properly mortar and joint the joint.

that the mortar joint according to DIN EN 1996-2 has a reference dimension of 10 mm.

That’s how I know it too, but I have not dealt with the tolerance in the standard. The estimated partly just under 8 mm I would not object to on a plastered wall, only on exposed masonry surfaces do I expect more meticulousness.