You have a small firm. You want to be "connected" at all times. If an important client calls, you want to be able to answer that call, whether you are in the office, on the road, or making s'mores in the mountains (assuming you have cell service up there).
This is what Google Voice used to be good at: forwarding incoming calls from your Google Voice phone number to anywhere (landline, cell, computer). But, the app hadn't been updated in years for either iOS or Android. Plus, it was pretty much for incoming calls only -- dial out on your phone and you've just given that client your cell number. (There was a workaround for Android that spoofed your Google Voice number, but thanks to the core app's stagnation, it was a pain to use.)
Well, Google just fixed everything. Kinda. Google Voice is now (mostly) integrated in its Hangouts app, which means a free business phone number, free VoIP services to the U.S. and Canada, free texting, and only a slight headache, though we'll try to simplify it a bit.