Continuing this here where it’s more relevant
That’s true, but at the same time you have to draw a line somewhere. There could be “All modes A and metro zone B fare” but that’s getting too complex for most people. In Laval you’d already need a different fare to enter previously, my monthly pass I bought in Montreal wouldn’t work there.
To compare to Panama, this has been a bus terminal since the 90s (RTL started in the 70s) and people would connect from there into the city and either walk or also take the metro, this new REM/RTL fare is essentially continuing that.