Like the title says, is there a particular reason to use the Truss em up skill? It doesn't really seem to serve a purpose in defeating enemies, since the only time you can use it is if they're helpless which happens when they're defeated or almost defeated already. Also, it seems much more useful to just sell the bondage gear for lots and lots of money.

1. You can use it on a stunned enemy which doesnt necessarily mean they are helpless and defeated already
2. After a certain point the ‘trash’ restraints you get will be worth very little due to the depreciation, so they might be worth spending instead of mana.

Also different restraints have different status effects. Armbinders can disarm, gags silence spellcasters, etc. It might be useful to turn a stun into a status effect when fighting a tough enemy like a conjurer.

Unless you specialise in the leather magic tree, which has a lot of specialised restraints for dealing status effects, dropping a quick stun and then forcing on a bit of bondage gear can be really powerful. God knows enemies putting security locked mana drain ballgags onto me tends to mess my runs up something fierce.

For the most part I've gotten good at drowning people in Latex attacks or use powered through with minimal spells.

I do see what you're saying though, and I suspect it will be far more useful on higher levels.