Not misleading and fairly standard practice. There is no value starting at 0 when the lowest device tested is 55, all you'd do is shift everything to the right or make it smaller and harder to see the distribution (which is the whole point showing the distribution from 55 to 123).
As long as the graph goes up in consistent increments (in this case 10) and shows that all these devices could move to the left (i.e. get quicker than 55) I'd say the graph has done its job.
Imagine if the x axis started at 50. The difference between the iPhone 5s and the next one would look massive -- much more than the 2-2.5x it is. That a lot of people do it ("standard practice") does not mean its not slightly misleading.
No, it's misleading and terrible practice that is only used to introduce bias. It is absolutely unacceptable to hide origin point on histograms because it obscures the relative comparison between values.
As long as the graph goes up in consistent increments (in this case 10) and shows that all these devices could move to the left (i.e. get quicker than 55) I'd say the graph has done its job.