We'll only know this when the games matter. As much as I am liking this recent form, Everton winning games that don't matter is nothing new. The only remaining acid tests this season are the Anfield derby and if we get close enough to teams above us that the league games become significant. Winning multiple games on a row knowing that regardless of the score you're not moving up or down from 7th has always been easy for this group of players.
So far this season we've not won away from home at any of the top 6, we lost the Derby, and we lost both cup games. The three most important games of the season so far have all been at Goodison and we lost to a championship side, a relegation struggler, and a Liverpool team who now can't buy a win. The rest of the season in all the games that don't really matter surprise surprise we're unbeaten at Goodison.
This group of players bottle when any pressure whatsoever is on. It's Koeman's biggest task to change that mindset.