The wording might be tricky , but read again carefully , ALL and ibis business are two separate things , the discount is only for ibis brands , while the benefits can be apply to ALL all brands (if available of course) .

"The card offers discounts and benefits in over 2,000 participating hotels across the world (outside of China)" then it refers to a pdf document with the non participating hotels of the ibis business

In the same page they mention that "***ALL benefits are only guaranteed in hotels participating to this same program. See the list of non-participating hotels" , and this is what probably tricked you