In our new house hubby poured thin layer of concrete over existing slab in ensuite and main bathroom, embedding coloured stones in it. It's been polished and sealed with crushed glass added just to the shower area .... we definitely won't slip on it, but will have to use a soft broom to clean shower area, as it would shred the pad on my mop (we haven't moved in yet).

Here's the pic from there, why do you want it? I'm wondering if the extra corner might be a trip hazard

They are probably concerned that silicon becomes mouldy. If you are happy to resilicone every 8-10 years it shouldn't be a problem. My main concern would be the very slippery surface you would be creating which may be a safety problem.

I am struggling to find any pictures of where someone has the shower fittings higher than their shower screen to see how odd it actually would look like. One of my 101 learnings about getting the wrong tradesperson to "project manage" my bathroom renovation (until he went MIA), was not voicing louder to the plumber's assistant who actually did the shower connections, that what the "project manager" had suggested for heights of shower connections was way too high. I had actually double-checked it on the previous weekend with a friend and we both thought that it needed to be lowered by 100-150 mm, but when I said this to the "project manager" he ignored me as did the plumber assistant who made the connections....I know how a handheld shower only (which is all I wanted) fitting that is at 2070mm in one bathroom and 2020mm in the other bathroom. As there is no shower rail (because I wanted things to look simple), I get my daily stretches just to reach the handheld shower.....I am happy with the progress of my bathroom, except for all of the stuffups caused by this particular "tradesperson/project manager". We live and learn....I can't do anything about what has happened, but can only minimise the impact where possible and learn from all the things that went wrong, if there is ever a next time. I should make a list of the learnings once bathroom is finished.