Your assets are held separately from Wahed's own money by an independent trustee. Wahed cannot use client assets for its own purposes, and if Wahed ceased to operate, your holdings would not be part of its estate.
One thing to be clear about: Wahed products are not PIDM protected. PIDM covers bank deposits and takaful, not investment products. This applies to ESA too, even though it behaves like a savings account.
Separately, protection from company failure is not protection from market movement. Your investments can still lose value.