Thse bugs first started loving my plants when they were about 1 ft high. I never see holes in the leaves they're on, so I don't think they're doing any harm. They are striped, flying insects.
i cant be certain from the pictures, but they could be leaf hoppers. If i am not mistaken, they suck "plant juice" from your plants leaves/stem. They dont leave many, if any holes behind. I believe they are rarely fatal to cannabis plants, let alone any plant but they can take a toll on you're plants if there is a large infestation. They are also known to carry viruses that can harm the plants. i have battled leaf hoppers in the past and in my experience they are fairly easy to eradicate. I would not worry too much as long as you're plants continue to show healthy growth.
I have a plant outdoors, and I've seen similar insects on mine. From what I can tell on my girls the insects are whiteflies & aphids. I started noticing a lot less though once my girl started flowering. Whiteflies are generally not a big deal when it comes to marijuana. What is a big deal is the "honeydew" they secrete on the plants leaves. This honeydew makes a the leaves more ideal for black spot mold which will kill your plant. Best thing you could do to guarantee harvest is to purchase green lacewing eggs or larvae. (the eggs are substantially cheaper then the larvae) The larvae are voracious eaters & eat any insect they can get there little insect hands on. They are literally a god send when it comes to outdoor growing.
These bugs don't look like aphids or white flies to me, And vdude white flies are most definitely a big concern!! I have seen whiteflies take over huge tomato plants over the course of only a couple weeks! As to the OP, I would say that it does look like a leaf hopper and I have always had these bugs on my plants and never noticed any damage from them so they shouldn't be too harmful to your garden.