With the recent mobile update, one thing is for certain, Google will go any extra steps to demote a site that don’t provide a decent search experience on a mobile device. That means any website’s element, be it a pop-up, non-responsive design, unresponsive buttons, slow speed, or anything that makes the website unusable or irrelevant, hampering a user’s browsing experience on a mobile device can get it penalized.
One of the persistent annoyance for smartphone users, nowadays, while browsing the web is interstitial pages, a website element that not only harms a website’s credibility but also the user’s experience.