Google first introduced this feature with the launch of Lollipop on the Motorola Nexus 6 to show off the OS' new ability to show individual app processes among other apps in the multitasking window. Although, putting Chrome's tabs in the app switcher makes it so easy to lose a past tab and makes it impossible to clear all Chrome tabs. As of version 49, the Chrome app no longer defaults this option of putting every single Chrome tab in the app switcher. Most people may not care about this, but this is more for people who are constantly getting new phones or always wiping their phones for a...
Source: http://www.gsmarena.com/finally_chrome_mobile_defaults_to_tab_switching_within_the_app_no_more_missing_tabs-news-17291.php
