Google Ranking Factor – Hover
The ability to hover over a target is only possible via a pointing device like a mouse, so any website that has functions controlled by ‘on-hover’ commands will make those features impossible to use without a alternative method being available.
Failing to account for this issue may make mobile and tablet user interface and user experience less than ideal, even if the website is responsive and has re-configured layout for the device.
Best practice when making a website mobile friendly is to test on a mobile device instead of just using a reduced browser window size on desktop or laptop, so that you can assess the usability of the site more accurately.
Excessive loss of functionality through loss the features due to this issue may be a ranking factor being considered.