When I use a helicoil to fix a stripped bolt or sparkplug in a car, I just have to get a new set of threads (the helicoil itself) in the right spot with enough strength so the old bolt or plug will work the same as before, as in bolting an exhaust manifold flange to the engine block. If the angle is off a bit it's probably ok.

With a pedal, the helicoil has to be installed so the pedal points in the exact same direction relative to the crank arm as it did before, or that pedal will feel bent when you ride the bike. This makes helicoil-ing a pedal a very difficult project vs fixing a stripped bolt on a '97 Dodge. I have no doubt it would be strong enough. A hand drill and a regular bit is going to take some luck to get the hole aimed just right.

Check with AutoZone, Advance, etc. They may have kits you can rent. I would just look for an arm on fleabay. But if you're the adventurous type then go for it.