Is there any advantage to add points to ability instead of Edge?

I have two abilities: Flash and Onslaught. If I spend one point with any of them, I will get 15% on attack with that specific ability.

On the other hand, if I add an Edge on Intellect, not only I will have those 15% "for free", but it will also improve other Intellect checks.

So, is there a justification to add points to those abilities instead of adding edge?

Solution 1:

If you can choose, always choose Edge, since indeed it increases your skill chance the same way as investing in skill and it works on multiple skills. However, if my memory is right, you are not always able to level the Edge when you level up.