Beneficiaries have no claim to any portion of the trust income. They only receive a benefit when the trustee exercises their discretion and distributes the income. The effect is that a person’s status as a beneficiary does not result in a tangible gain or proprietary interest in the trust property. As there is no claim to the property, you are not subject to tax implications if you do not receive a distribution.
Disadvantages can include that the trustee can stop distributions to a particular beneficiary at any time. Likewise, a beneficiary can do little to change this arrangement. This can present a problem should a dispute arise with the trustee, for example, a family fall out. This is a key reason why you should exercise great care when selecting a trustee.