From a historical perspective are there any practical applications of the meson or pi-meson?

The long-range forces holding together nuclei are transmitted by pions which can be described with Yukawa's potential. This is very much what he described. See https://en.wikipedia.org/wiki/Nuclear_force

So in that sense, while not fundamental, pions do find an application in any nuclear reactor or atomic bomb.

Now Yukawa was mistaken in that he assumed that the exchanged particle would be the particle found in the cosmic radiation (which we now call muon). But that error is forgivable because he fell into an elaborate trap laid by nature: on the one hand, it is an accident of nature (the pion being the Goldstone bosons of unbroken isospin symmetry) that the pion's mass is so low and thus so close to the muon mass. On the other hand, the source of the muons of the cosmic radiation actually are nuclear reactions: solar and galactical protons hit the atmosphere and undergo nuclear reactions. These reactions produce pions, some of which proceed towards the lower atmosphere. But what Yukawa couldn't know is that the pions decay before reaching the surface. The particle they decay into is the muon. Not knowing about the subsequent decay, one would therefore assume that the cosmic ray particle actually participates in nuclear reactions.

Additionally, pions serve as source of polarized muons which are useful tools for study. They are one of the main tools of study at the fixed-target experiments in CERN's North Area.