As others have said, there's nothing implicitly wrong with a looping approach shot. Just don't assume it will work against everybody.
In the same way, one shouldn't assume that conventional wisdom will work against everybody, either. In other words, just because dogma and yes, even percentages, suggest that slice approaches down the line tend to be the better choice - you found out against this particular opponent that this is not true.
I think changing it up was the right thing to do. You could have been one of those players that stubbornly sticks to a losing (though "correct") game plan - and you would have lost.
Really - neither I nor my opponent is there to make each other feel good about our respective games. If he can't effectively respond to shots or situations that I can more easily maneuver him into, then that's just too bad for him - and same for me if vice versa.
We'd all like to win with aces and winners - but even pros give away more points than they win, on average. I'm honestly amazed more hackers haven't figured this out.
Oh well, more wins for me - and you, if you're smart. Loop on, man - unless that doesn't work, in which case figure something else out.
Nobody paid for the opinions I express.