Oh? I'd like to know the source of your "impression".

For me, lack of provision for cargo is no more than an inconvenience, indeed, a minor one. But one of the foresighted aspects of Citibike is that NYC public housing residents get a very substantial membership discount. One obvious reason: public housing isn't always well-served by conventional public transit. A not-so-obvious reason: public housing has no commercial activity. None. No food stores. No services. Some public housing is within bike share's service area, but anything / everything you need to live is Away. Sometimes Far Away.

Is shopping by bike appropriate for everyone? Of course not! But omitting the option to schlep bulky stuff using bike share shows limited vision.