Don't know how friendlies portaying an overusage of looping arrows means that they've almost mastered it. Yass and his buddy missed looped arrows 90% of the time and when they hit there was hardly any gain from it rather than shooting 2-3 straight arrows. Its cool, but still not practical.
Thats why AP began beating me more in our friendlies, he's a straight and narrow pit, and arrow looping simply doesn't work well for the Pit using it in the ditto. Smarts and technical prowess however do. He's great at platform canceling.
Also, arrow looping is significant in certain matchups, not so much in others. Ever pelted a MK multiple times just because he decided to glide to you from a distance? You pull an arrow while he's jumping, shoot it behind you, loop it, hit him in his glide (it's the perfect distance for the loop to be more accurate) and then shoot him again. THAT'LL TEACH THAT BAT TO GLIDE AT ALL!!
Also, looping in a match up where the opposing character has his own projectiles is very useful, but not against characters like Pit, ZSS, or even Shiek. They all have tools to negate, avoid, and even punish you for using them. (plus they're skinny as hell and hard to aim for anyways)...
Finally, big mistakes from Arrow looping will cause you a lot of punishment if you use them against characters like Dedede, even if they are useful because he's so fast, you get like, 4 percent if you hit? He gets like 20 percent after getting hit because he grabs you almost immediately if he's made it that close to you during the loop (which he will)...
Snake is the only exception, arrow looping helps immensely against him because it pressures him to keep moving and shielding which you can use to bait for a grab, punish of some sort, and then getting him in the (his most vulnerable period) is that much easier. But again, focusing on ALing will just hurt you in the end, because snake is an even matchup not because we can pelt him with looped arrows easier without fear of him being a fat-***-hitbox like Dedede sticking his foot out 2 or 3 times in 2 seconds...