Unfortunately it's a trend for Google to lose features in replacements and event new versions sometimes. I use Inbox for my personal gmail account, because I like how it lets me manage my personal mail. Unfortunately, there's still some integrations with calendars and stuff that doesn't work in Inbox but works in Gmail. And you can't search hangouts in Inbox (even though hangouts is integrated into it). Want to search hangouts message history? Open a tab and sign into gmail, and use that. Seriously, why do I have to lose so much of the functionality I grew accustomed to in the past when the app is from the same company? So frustrating.