I have asked here whether, in order to establish causal relationships, the treated group and the control group must be similar on all covariates.
The answer was no, if we control for the covariates in an OLS regression.
So what are the use cases for Propensity Score Matching?
Why I can't just run an OLS regression controlling for the covariates on which the two groups (treated and control) differ?
EDIT: The problem is that my colleague is saying that the OLS I proposed in the linked question will not work and we need to use Propensity Score Matching. Wikipedia is saying the opposite:
This blocking can be done either by adding the confounding variable as a control in regression, or by matching on the confounding variable.
So, according to Wikipedia, either adding the variables as controls or using Propensity Score Matching will work just fine both ways
EDIT: The topic is also covered in this video at minute 12:00