I'm no expert but i'll give it a shot:
Jägermeister and other herbal liqueurs do contain herbal essences that probably have some effect on your body. But not in any medicinal quality, otherwise it couldn't be sold as food in the EU by law. There are strict rules (e.g. Directive 2001/83/EC).
In general the usefulness of digestifs for the digestion is heavily discussed (there are opinions that the alcohol takes away any positive effect the herbs might have). But i don't have any reliable sources at hand.
And the alcohol is unhealthy, no doubt.
So from a medicinal point of view: stay away from digestifs and stop eating too much so you won't need any digestion-helper.
From a recreational or culinary point of view: If you enjoy the taste, a digestif is a great closure of a good meal and the psychological effect of "believing it helps" works sometimes.
And i personally like the taste and drink it recreationally and not just as digestif ;)