Looks like a bit of overpriced rubbish to me! I used proper reins for ds1 when ds2 was born (16m) gap. Just keeps em safe stops them running in the road and if they trip you can stop them falling. And they are usually only about a fiver. If you only have one child you would probably manage with hand holding.
Apparently South American parents use a long scarf under children's arms and it works really well. Imho you can manage without anyway.
Whether you'll need normal reins depends on how many children you have at the time and whether yours is a running off type or not. Ds happily holds my hand and is too wussy to run off so I've never needed them.
I am not tall, but when ds1 was on reins I only clipped the parents-holding-bit to the side of him nearest me, otherwise he'd have been walking into the pram all the time. That gave him a bit of support. I think the scarf thing sounds like a really good idea though if you want it to steady the child and not for safety. There are some gorgeous ones in the shops at the moment and then you get to use it for a scarf next winter
We have the Littlelife backpack too. The handle is very useful even if the rein bit isn't attached if you just want to grab hold of a fleeing child.
I would be wary of anything that was sold as 'helping' walking - children learn to walk perfectly well by themselves. However, I'm all for things that help mummies. Not convinced by the bikeriding pic, but the rollerblading looks fun.
I wouldn't buy 'regular reins' to give confidence. However i would like somehting which would give her a bit of support so i dont have to constantly lean over to hold her hand as this is very painful. Think we may try the scarf idea...just to see if it helps, plus its free!