Yes but that can be a benefit too... after all no one else is going to pick it up and use it against you either.
I'm not sure I understand the benefit of enchanting an item that you have an arcane bond with. Is the only benefit that you don't need the pre-req item creation feat to enchant it? The way I read it, it costs the same as enchanting a non-bonded item, but only the wizard who crafted it can use it? Am I reading this right?
Yes.
For example if I choose my sword as a bonded item I can enchant it as a weapon at 5th caster level without needing the Craft Magic Arms and Armor feat. AFAIK that's the only pre-requisite that you can bypass, and must still meet other prerequisites for the magic item you are crafting, including caster level and spells known. It is no cheaper.
Also From PHB:
The following are the class features of the wizard.
A bonded object can be used once per day to cast any one
spell that the wizard has in his spellbook and is capable of
casting, even if the spell is not prepared. This spell is treated
like any other spell cast by the wizard, including casting time,
duration, and other effects dependent on the wizard’s level.
This spell cannot be modified by metamagic feats or other
abilities. The bonded object cannot be used to cast spells
from the wizard’s opposition schools (see arcane school).
This is REALLY useful. More than once I've played wizards that had The Perfect spell for a given situation in there spell book, but didn't memorize it. This helps wizards be Really impressive and give the appearance of being able to do anything.
Agreed on the usefulness part. But having your spell casting tied so closely to an object makes me hesitate. At mid to low levels, being deprived of the item can be a real kick in the teeth.