I want to put a raised bed on the lawn, right against the fence. However, I wanted to use this type of siding/edging on it's own instead of those lumbar raised bed kits. Will this work or do I have to use one of those raised bed boxes?
I think you'll need a rigid framework (like a raised bed kit) to hold the soil/compost or it will be impossible for it to hold it's own shape and will be unstable - you could then attach the log roll edging if that's the look you're after.
I find it best to line the inside 'walls' of raised beds with thick polythene (I staple it to the wood) as that helps prevent the wood from rotting. I also line the base with permeable membrane so that the soil doesn't wash out of the bottom of the container.
Get some 2x2 tanalised wood and cut it into stakes with a point.
Hammer them into the ground to the height of your log roll and screw the roll to the stake.
I have two beds raised like that and they are now well into old age and still good, the stakes need to be no more than 18 inches apart for stability, and I lined the back with old plastic compost bag cut to size, worked for me.