Hey Ruben,
I use our number on the meta description of our site (MarbleRenovation) and it works wonders for us. I noticed a spike in calls once we had included it.
It makes sense... People don't want to think too much nor search too hard to get what they want. If they see a number from a company that is high on page one for a term they have entered then they are likely to call it without even looking at the page. Obviously this wouldn't work for all industries but if it is advice you need, a number sometimes is enough for them.
Hope this helps amigo!
Dave