I may be old fashioned but I think there is a role for both.
As far as traffic goes , my smartphone loaded with Waze is vastly superior to my SatrNav. Just today I ran both in parallel as an experiment. The Garmin predicted an arrival time of 13.02 for a tortuous cross London route of about 1 hour. The Garmin gave a time of 13.29! I actually arrived in 13.03 which I reckon was pretty good.
However if I want to start a journey in an area where is no phone reception (say middle of Exmoor) then the Garmin 2599 will pick up satellites in a minute or so , lock on , and I am away. I wouldn't want to rely on only one system.
