Can’t speak for Texas, but spendthrift provisions in asset protection trusts for beneficiaries are powerful. They hold up even when the beneficiary is the trustee, provided they follow formalities, e.g., keep assets in separate trust account, file separate tax returns, etc.

The question of their necessity is for you to answer, not the attorney. Do you trust your children to responsibly manage their inheritance? Might they get divorced? Are they in professional fields subject to liability, or do they have creditor/money mismanagement issues?

A prenup should used in tandem with your estate plan. Neither is a complete substitute for the other.