Nydus worm can be very effective in many different use cases.
Combat: All you need for a nydus worm deployment is line of sight which you can easily achieve with an overlord/overseer. This can be an effective way to get through a walled in opponent without actually taking out their wall. Nydus worms also generate creep so you could even setup spine crawlers if you so wish.
Another way to use it in combat is to distract your opponent. Because the nydus worm can be heard anywhere, they usually go into panic mode and will send their army back to their base or will be otherwise distracted in scouting for it at which point you can attack with your army without actually using the worm.
Its also important to note that when a nydus worm node is destroyed the units inside are unharmed unlike a warp prism, medivac, overlord. Unless you take out the whole network.
Economy:
This is a bit tricky and requires you to be on top of things micro wise. But you can use a nydus worm to mine out an undefended high yield without actually building a hatchery there.
Setup the nydus worm in your base right next to your hatchery and set the rally point to your hatchery then shift click back to the node. Then where you've opened the nydus worm at the high yield, set its rally point to the minerals then back to the worm.
Hot key your nydus worm's mineral node to a key and the base node to a key. Load it up with a bunch of drones then every 20 seconds (i forget the exact timing) select the opposing nydus node hotkey and press 'D'. this will unload your drones, and depending on which side they unloaded they will either start mining or they will return the goods back to your hatchery.
Obviously this use is very complex and requires you to remember to unload and at which node to unload at (have the drones just mined or just returned gathered minerals?). You also lose the added benefit of having more larva and another hatchery.
Best Answer
They use the ranged upgrade.
If you open up the galaxy editor and look at the Hydralisk/Roach you'll notice that they have two different weapons: one for range, one for melee. You'll notice that both of these attacks have the same upgrade specified.
Here we see the relationship between
Zerg Missile AttacksandHydralisk MeleeIf select
Zerg Missile Attacksand selectUpgrade Effects+we can see where the association is set