When it comes to effective communications size does truly matter, size of the device that is.
Different endpoint devices are better suited to different modalities of communication, and different endpoint types are best suited to use in different locations.
While it may seem that smartphones and tablet devices are "taking over the world", we should all pause for a moment and consider how the various communication modalities will work on these devices and where our users plan to use them.
Most smartphones, in addition to being "smart", i.e. running lots of applications, are also quite capable phones. Like one would expect from a phone, a smartphone can be held close to one’s ear so that the conversation (at least the other participant’s speaking) is private.
Smartphones also can be held easily in one hand so that even while in motion, walking or driving in a car, singlehanded operation is possible. And, in an increasing number of jurisdictions where hands-free operation in vehicles is mandated, almost all smartphones support Bluetooth headsets and most smartphones support some form of voice dialing (which often actually works!) so that driving and dialing can be done relatively safely.
Email and instant messaging on a smartphone are possible; however, reading is generally easier than composing, especially given the smaller size of touchscreen keyboards--and the smaller screen sizes make deciphering complicated documents such as spreadsheets challenging.
On the other hand, clearly a tablet and email or instant messaging can work very nicely. Viewing document content, for example a slide presentation or a detailed spreadsheet, on a tablet, likewise works well given the larger screen size. Almost any document or spreadsheet can easily be viewed and understood on a tablet.
However, tablets, though they may be "smart," are not very good phones.
For tablets, it is communication modalities that involve audio that may pose the biggest dilemma. A voice call works ok but it is akin to using a speaker phone unless one quickly plugs in a headset or activates a Bluetooth headset. And one of the things that makes a tablet better than a laptop is that it is typically used in a self-contained mode without additional items to carry and plug in.
So, if you receive a call as you are working on a tablet, you may end up trying to hold the tablet up to your ear, which looks ungainly and is not suited for calls of any duration.
In the end, different devices have different form factors for a reason. Each of these form factors is designed for and well suited to particular user experiences.
Size does matter. And beyond size, we should remember that a smartphone is not a tablet and a tablet is not a laptop and a laptop is not a desktop computer. And of course, none of the aforementioned are desk phones.
A deskphone has some unique attributes, some positive and some negative, depending on your specific requirements. Not all deskphones are "bad" and getting rid of all the deskphones might not be "good".
Unifying our communications is not about finding one device to service all of our communication needs but rather about allowing users to make use of different devices in a familiar and similar fashion while representing and embracing the unique attributes of each device.
In order to provide an effective communication solution, most importantly, the devices purchased and deployed need to match the requirements of the end users.
Size does matter, but one size definitely does not fit all.
