Sometimes a keyboard may be the only way a person can use a computer. This has been mentioned already, but your tab ordering and keyboard support has to be on point. The best way to show this again is to use a screen reader and test out the examples.
See the Pen Good tab order example by Kyle Bacon (@l3acon) on CodePen.
See the Pen Bad tab order example by Kyle Bacon (@l3acon) on CodePen.