I have met plenty of things where my insane arrows saved my life, mostly because I play with multiple dungeon mods, gravestones, and Twilight Forest. Lots of things from those mods definitely need more than 4 hearts of damage. Also, 12 hearts won't insta-kill an angry zombie. The reason for the paper is because it's cheaper, and there is no durability on the arrows. Thaumium is one of the first materials you research, and you can often find it as loot. Also, I do have Mekanism, because Mekanism rules.Has this changed recently? Because last time I used a TiCo arrow as a melee weapon, it didn't do any more damage than your regular unarmed attack.
Also, that's an awful lot of resources there for a single stack of arrows, which you can't guarantee you can recover. Particularly the Thaumium (although my problem there is that I absolutely despise the cauldron as it currently stands).
There is absolutely ZERO difference between a Thaumic Guard and a Paper one. They both add an additional modifier, and the guard has no other impact on the weapon itself. Plus 14 hearts (much less 30) is ridiculously over-engineered. You will never meet anything (barring wither or nether dragon) which requires that sort of damage output. 10 hearts is more than enough to one-hit kill anything you are likely to encounter, unless you have Mekanism and every skeleton and zombie is blinged out in armor.