Eriksen is a decent bit better than Coutinho yes.
No he isn't at at all actually.
And is pretty obvious why Barca went for Coutinho instead of Eriksen, he has more star quality, inspiration, as well as a better tighter technical game. Where you can say Eriksen betters a bit is by his decision making, and his propensity to play in a midfield position, this is what i'm seeing argued here, but actually Coutinhos last 5 games have all been in cm, all produced good performances and even going back 13-14, he already has a season where he was performing as one of the better side/cms in the league.
In terms of him being better at Coutinho at everything, its a myth, and maybe confirmation bias. He isn't a more consistent passer than Coutinho, per 90 Coutinho betters him with his pass completion, he isn't a better tackler, per 90 Coutinho again more tackles, more interceptions, and more goals. Where he bettered Coutinho last season was in his creative stats, more key passes and more chances created, but that was really it.
If we're looking at what Barca want in an Iniesta replacement, then Coutinho suits them more, as he is a bit more mecurial, more of a maverick and can take 2, 3 players out of the game consistently, leaving space for the likes of Messi and co.
Eriksen doesn't do this half as well, and in the position Iniesta plays the ability to carry the ball forward in short turns and dribbles is paramount, its also quite handy when you get a tight game and you have a player away from your front stars like Messi Dembele and Suarez, who can take the ball upon himself and smash it in the net like Iniesta used to in key moments in key games, when everyone else was suffocated.
