I'll respond to this just because I'm a numbers geek. The point of this argument is answering the question of what minimizes your overall score in the long run, playing the same hole over and over again. What variables do we need to consider? Your GIR % when aiming at the pin and the center of the green, your up and down percentage from near the green, and your percentage of birdies and 3-putts resulting from your approach when you hit the green with those two aim points. We'll ignore chip-ins and 3-putts when you miss the green, though I'd bet ignoring both of those biases the results below in favor of aiming at the pin.
The 100th best U/D % on tour last year when scrambling not from the sand in 10-20 yards was 60% (Davis Love III). The 100th best % from the fringe was 87.5%. I'll be very generous and give the player graphed below 65% U/D when missing the green on the sort of non-dangerous hole with an easy green you describe. As a 4.6, I assume you 3-putt rarely. Below I've assumed that you 3-putt 2% of the time when you hit the green when aiming for the pin and 4% of the time when aiming at the center of the green. The increase in that case is due to the fact that you'll hit the green but be very far from the hole more often.
The key variables are the difference in GIR % and the difference in birdie % for the two strategies. Below are 4 graphs that give results for when your GIR % decreases by 5%, 10%, 15%, and 20% when aiming at the pin versus aiming at the green center. I've graphed your expected score over a range of GIR %s. I've given the player aiming for the center of the green a birdie only 5% of the time he hits the green (so if he hits the green 50% of the time, he's getting a birdie 2.5% of the time, which I think is quite low for a good player with a PW approach to an easy green). Then I've graphed the expected score for a player going at the pin when he expects to get a birdie 10% and 20% of the time he hits the green, taking into account the decreased GIR %.
Think about what these mean. When the red line is below the black line(s), the expected score aiming at the center of the green is better. These are assuming an unrealistically good 65% U/D, better than Davis Love III from right next to the green but off the fringe. It also assumes you never flub a chip and don't get on the green or thin one way long and then 3-putt. Consider the top right graph. This tells you that even with this unrealistically optimistic percentage for U/D and failing to get home in 2 or 3 strokes 0% of the time, you need to believe that you expect to hit the green at least 60% of the time aiming for the center, you're only decreasing your GIR % by 10% going at a tucked pin, and that you get double the birdies by going for the pin.
If you accept that you'll decrease your GIR by 15%, then you need to think you're quadrupling the number of birdies you hit by going for the pin to ever go for the pin, no matter how high a percentage of the time you think you could hit the green aiming for the center.
The point of all this is that unless you think you have tour level precision with your scoring irons, it's almost inarguable that you're giving away strokes going for the pin. I fall victim to the psychology of it being more fun to attack pins on easy greens cause it's really fun to hit one just like you want and get an easy birdie putt, and you like to think to yourself that it's not that penal and you're not giving away much if you miss a tad. But if you look at these numbers and think about what's probably closer to the truth with a 9i, or 8i, or how often you underestimate the penalty you'll pay on any given hole because it's more fun to attack the pin and in general you play better when you're confident, you're probably giving away at least a stroke or two on average per round by attacking pins with our amateur skills.
I'm interested to see the actual results over a range of handicaps!
More important is how long it took you to write that all while thinking about it and then put the numbers in the graph formulas and format the graphs.. Also was it during work hours!! :)