Despite disappointment on the pitch for Poland and Ukraine's chances of reaching the quarter-finals depending on them beating England in their final group match, Platini said both countries could be proud of what they had delivered after problematic preparations, mainly involving infrastructure.
"It's not been perfect but I'm very very happy," Platini said of the biggest sporting event to be staged in eastern Europe since the Berlin Wall fell.
"Poland and Ukraine have delivered. People (of Poland and Ukraine) are saying thanks that you had confidence and trust in us.
"They have already won the Euros. The Championship can bring lots of very important things for the development of these countries."
With the group stage reaching its climax on Tuesday, Platini, speaking over lunch at a restaurant in Warsaw's leafy Lazienki Park, hailed the tournament a big success, characterised by plenty of goals, good matches, consistently good refereeing and only "one or two" problems.
"The atmosphere in the stadiums has been 99.9 percent fantastic," said Platini, picking out the Poland v Russia and Ukraine v Sweden games as "extraordinary" to be present at.
"It's difficult to do better than we have done. But doing better would mean perfection."
Platini's relaxed demeanour momentarily changed when asked to address the problem of racism during the tournament, with Croatia's Football Federation facing a UEFA charge for racist chants by the national team's fans in the Group C match against Italy in Poznan on Thursday.
A stern Platini said he had held talks with Croatian government ministers a year ago when he expressed his concerns over the behaviour of their fans.
"How can you manage stupid people?," he said, referring to the fans who chanted obscenities at Italy striker Mario Balotelli.
"It's a matter of society and education. It's not just in eastern Europe, there is nationalism in all countries.
"But one case (of racism) is one too many."
Turning back to matches during Euro 2012, Platini scoffed at pre-tournament suggestions in some quarters that holders Spain, bidding to become the first side to win three successive international titles, could be tired.
"The ball is tired, not the (Spanish) players," Platini joked.
"They have a style and a system where tiredness is not a problem."
Casting his eyes over the other teams, Platini said he had been "surprised" by Italy's more expansive game.
"(Coach Cesare) Prandelli has made Italy play. It's beautiful," he said.
Platini has watched games at every tournament match venue except Poznan where he will be for Italy's clash with Ireland later on Sunday.
While the Netherlands, eliminated on Sunday after finishing bottom of Group B with three defeats, had been a "disappointment", Platini pointed to their demise as a sign that the European Championship was a "more difficult" competition than the World Cup finals.