Beguiler/Wizard/Ultimate Magus and ban enchantment/illusion

[With a box]

the obvious one, Beguiler 1/Wizard 4/Ultimate Magus 10+ something (archmage, I think)

1. Can it be fluffy justified to ban illusion or enchantment?
Like, did I studied on these or not?
2. Will I miss high level illusion/enchantment spells witch can't get from Beguiler side?

[Urpriest]

For the fluff justification, I tend to like the idea that, since you were naturally gifted with illusion and enchantment, you never bothered to study them.

There's some high level content that's nice to have. If you wanted to use Mindrape, or the Simulacrum line, you'd be out of luck. That said, if you would have avoided those things due to their brokenness then there isn't a lot of other high-level tricks that you'd be missing.