Having Poland with 4pts Argentina with 3pts Saudi Arabia 3pts and Mexico with 1pts, the game between Poland vs Argentina is going to be a cracker because both teams need the winning to qualify to the next round. I think they'll share the point, it will be a draw. Argentina need to top the group so as Poland, that's to say a winning must come in play but is something I don't think will happen, if it plays out to be a draw I see Mexico to get a win against Saudi Arabia and the table will be like
All teams still have their chances to end in a first two positions and both last matches are important for all. Argentina must win Poland if they don't want to bet that they will get a lucky ticket from Mexico. Poland with their players, will very hard to beat Argentina unless Argentina suicide in the match.
Saudi Arabia will not likely to have 3 points from Mexico and they will even have a loss and at the end, they might have similar ending like Iran yesterday.
Both Poland and Argentina often find it difficult to score goals or get deadlocks more often and therefore, in this decisive match it looks like Poland will take advantage of the situation to defend well.
Both teams don't want to fail in this match because if they fail, they will face with a very bad ending after all in this group. One point is better than a lose at any goal difference so I am sure they will begin this match with very high careful approach.
Although indeed, on paper at least Argentina has a better chance of winning and considering the predictions above, it seems that the victory obtained for one of these teams might only be a narrow victory, for example 1-0 or maybe 2-0.
But I also bet for Argentina and I still got odds @1.48 on stake.com a few hours ago, but now the odds have dropped and maybe with the lowered odds it looks like Argentina will indeed win.
Argentina have more good attacking players than Poland especially Messi who can decide a match with either one shot (like a goal he scored in a match with Mexico) or opportunities he can support his team mates. If a match result simply depends on odds on sportsbook, gamblers should win a lot but I agree with you that Argentina have more chance to win this match.