I think it is because if the tap handle doesn’t overhang the sink then wet hands drip water over the bench behind the sink. I have an undermount sink with same issue due to required setback from sink and we are learning to shake hands before turning off tap. Pro for wall mount no gunk around base of tap Negative according to my husband who refused to have wall mounted is the tap connections are in wall so if you get any leaks it’s hard to fix. But this goes same for shower I guess. We did have a faulty basin tap that leaked inside the handle area and down into cabinet so had to get replaced so I didn’t-push for wall mounted again.

Just remember that good quality tapware is EXPENSIVE and so is the plumber to change out the tap so go for the best you can afford - tapware will either make or break the look you're going for in terms of big ticket items. But go for what you want - infact take a sample of your benchtop and put it next to the tap and a stainless steel appliance in the Ikea showroom and have a look to decide for yourself - it all depends on personal taste.

if you can find a suitable wall tap that is the correct length to have the water fall nicely into the basin then one advantage is that the wall tap takes up less space on the counter and there's less pipes work inside the vanity but...first check out the taps and see which one you can't live without.... as long as the tap does the job you will get used to whichever you choose...one of our vanities had to have wall taps for various reasons and we had to choose a spout from one design and a mixer handle from another...looks good and works fine

We have a zip built into our ceasar stone bench top next to our sink. We opted for the font (the mesh waste) and riser (it attaches to the bottom of the zip to give it extra height) We have instant boiling water (you can only use it when you press the safety switch located under the boiling water switch) chilled filted water and sparkling water. The sparkling water is sensational. We worked out the ratio and it is of equal value (replacing the canister as to buying X amount of bottles of mineral water over the same period) and we drink a lot of it (we are a family of 5) The unit itself sits under the sink and is smaller than a case of beer, and next to it is a C02 canister (resembling a small tube) We now don't have any empty water bottles in our fridge or cupboards, we no longer have a shelf full of mineral water (the filter water is so pure and clean) and I don't have a kettle on display day and night!! Yes the initial outlay is expensive but it looks fantastic is easy to use and I would highly recommend it.