In theory, yes. But looking at other ppl's cell phones (nooo, I'm not curious), I find they usually dont give a damn about which is which. Depending on their models, they have a choice of entering a home/cell/office/.../ numer - and with many people, in the end everythings all mixed up because they dont see why they should care.

Also, some folks have their contacts imported from whatever system they keep them... and you know strange things can happen when you sync contacts.

So in the end, I'd always prefer having to do this one extra click for selecting the actual cell phone number over pseudo-intelligent applications that think a number is a cell phone only because it's listed as one.

Oh, and one more thing:
Until recently, the company I work for (a telco) offered text messaging for land lines, including a gateway to cell phone networks of course. Which meant you could in fact send a text message to any land line (as long as the owner paid for this service).