While Root, England's Test captain, is sometimes referred to as one of the "big four" batsmen in contemporary international cricket alongside Kohli, Steve Smith and Kane Williamson, he admitted he wasn't sure he would "put myself in their bracket". Instead, talking in The Analyst's Virtual Cricket Club - an initiative set-up by Simon Hughes to support the Professional Cricketers' Trust - he accepted he could learn from all three of them.
And Root also tipped Buttler to convert his dominance in the white-ball game to Test cricket, comparing him to AB de Villiers in his ability to "demoralise" bowling attacks.
"I try not to measure myself against other players," Root said. "But I do watch a lot of how they go about constructing different types of innings across the three formats. You're looking at three of the greatest players the game has seen. They're three brilliant people to watch play and learn from. I'm not sure I'd put myself in their bracket, to be honest.
"I look at how late Kane plays the ball, how still and correct he is. How, under pressure, he finds a way to trust his defence on any given surface. That's a great quality to have.
"You look at Smith and at times he's just awful to watch. It's horrible on the eye. But you'd pay to have him in your team. He's a fantastic run-scorer. The way he thinks about the game and manages passages of play is exceptional. He makes bowlers bowl where he wants them to and his self-confidence you can see by the way he leaves the ball and some of his idiosyncrasies.
"He's always trying to find a way to get on top of the opposition. His hunger for big, big scores is fantastic.
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"Virat is probably the most complete player out of the three of them across formats. His ability to chase things down in the limited-overs format and to pace it as well as he does as often as he does and be not out at the end is extraordinary. He's got a very good all-round game but you wouldn't say he's weaker against spin or pace.
"He obviously struggled on his first tour to England, but he scored really heavily when he came back. And similarly, elsewhere in the world, he's put in massive performances. All that with the weight of India on his shoulders, as well."
While Root accepts that Buttler, at this stage of his career, has not dominated in Test cricket as he has in the white-ball game, he believes his improved Test batting in England's 2020 summer could act as a springboard. Buttler averaged 52.00 in England's six home Tests with one century and two high-class half-centuries.
"Jos has been the most complete white-ball batsman we've had ever," Root said. "The way he can play a number of different scenarios. He can just demoralise attacks and very quickly swing games massively in your favour.
"I think he's a phenomenal player and I still don't think we've seen the best of him yet. Hopefully this summer in Test cricket can unlock doors for him. I saw a piece about AB de Villiers and he said it took him 50 Tests to work out his Test game. I think it's very similar to Jos, to be honest."
After 50 Tests, de Villiers averaged 42.41 with eight centuries. This grew to 52.14 with 21 centuries after 100 Tests. Buttler has currently played 47 Tests and averages 33.90 with two centuries.
Meanwhile, Root confirmed England would return to training in a couple of weeks. As revealed by ESPNcricinfo, the ECB plan to erect a large marquee at their performance centre in Loughborough to enable to players to practice on turf wickets. And Root hopes the benefit of video analysis of his recent dismissals will enable him to rediscover his best form.
"Teams quickly find trends in ways you get out," Root said. "If you get out in similar fashion on three or four occasions, teams will be using that as a weapon to get you out.
"So, I sent an email to our analyst at the start of the week and said, 'can you please send me all my modes of dismissal over the last two years.' I want to look for trends within that and know if there's any patterns between 0-20 and 50-80. If there are elements of my game that seem to be constantly worked over, I can look at that and find ways to improve for the future."
George Dobell is a senior correspondent at ESPNcricinfo