The only times I allow it myself are in this case (zero legal availability) and for unofficial/fan translations of games not available in your home region/language. Nobody would be getting your money anyway, no theft of compensation/profits there. If any games do become available, though, then we should support them. The more we put our money where our mouth is for a return to market for these games, the more incentive there is for companies to bring more of them back.
I still have carts of Blazing Blade and Sacred Stones from back in the day and I primarily play those games on those carts with my old DS Lite. I have copies of all the Western released games in the series except the Tellius games because I don’t own a GameCube or Wii and the going prices for those games are ridonkulous anyway. Among those, the only ones I haven’t at least tried yet are the Fates games. Currently working my way through Echoes and its very different gameplay compared to the rest of the series.
Props to you for clearing it. I can’t play modern games on Classic mode, I get too attached to the characters and am not willing to either constantly reset or just keep going when one dies. Plus, I don’t exactly know if modern games are just harder or require more grinding (that they have the ability to grind in the first place is a modern thing), but characters seem to just die more easily in modern games, at least the way I play them. I’ve gotten to the point that deaths are rare in a replay of FE 7, but when I was playing through Engage, Awakening or Echoes they’re falling all over the place.