I think people undervalue Disrupt, myself included. With the main reason being that often, you won't be sure exactly how much of an impact you had. Sure, there's some cases it's obvious - they have a pay side and you disrupt their last resource or hold a Disrupt dice as insurance. You stop Crime Lord. The payout is obvious. But in many cases, it's hard, or impossible, to gauge exactly how much you set them back, or changed how they play. Maybe they were saving up for a 3 cost attachment next turn, and now they can't play it - but you don't see that. Maybe that resource you disrupted two turns ago is the one they needed to pay for a control card. Or maybe it's as simple as them taking a resource dice, instead of rerolling it into something 'better' - something you simply can't gauge in a lot of cases.
Statistically, compare the effect of disrupt to discard. Discard 1 hits 20% of their 'normal' resources (i.e. cards) for the turn - Disrupt takes out 50%. Discard 2 hits 40% of their cards, Disrupt 2 costs them an entire turn. Obviously there's a built in mechanic for getting more resources compared to cards, but still. Then you've got to consider the actual effect of Discard - yes, sometimes it'll hit the exact perfect card that you wanted to get out of their hand. But often, it's just hitting an option - the game is such that you usually can't afford to play everything in your hand each turn. You hit something good they were just about to play? Well, they still probably get to play something else anyway, even if it's worse than what they wanted to play. Hit their resources, and now maybe they don't get to play either card.
One big issue with disrupt is when to use it - specifically, you pretty much need to be using it as early in the turn as possible (unless you're holding it to stop them gaining resources in the turn). Even then, you're simply going to force them to use the resources as one of their first plays, which they probably want to do anyway in a lot of cases. There's definitely more times that Disupt is useless, compared to other dice. The other big issue right now, IMO, is where the Disrupt sides are. It's often on dice you probably don't really want to be using for Disrupt - damage dealers like Vader, dice with lots of focus or specials etc. And there's only a couple of cards that have more than one Disrupt face, so it's not really consistent. I think it'll probably see an increase in use if we see some cards that are more specialized towards choke, or at least Disrupt as the face you want to roll.