I freely admit that my fascination with winged hussars is immature. That doesn't change the fact that Poland is a state in search of security like all others, borders countries it regards as untrustworthy (Russia and Belarus), and has a largely flat topography that allows armored assault by those countries.

Of course you can argue that being a part of NATO means that they are under the US nuclear umbrella and therefore it is non-rational for them to invest money in military hardware. However a nuclear umbrella depends entirely upon the protector nation being able to credibly communicate that it is willing to use weapons in the defense of the client nation. This gives the client nation incentive to demonstrate that it has a spine of its own and is willing to pay a reasonably high cost to defend itself. Otherwise, who would believe that the larger nation would defend the smaller when push comes to shove? Why else would Poland have gone to war in Iraq?

The winged hussars are still silly, but a well-known elite cavalry unit doe support the narrative that Poland is a bulwark of the alliance against an assault from NATO's traditional enemy. Also, they could better support and possibly train their ally Ukraine.