Interesting to read the overview part.

'The ultimate goal of bicycle-sharing is to expand and integrate cycling into transportation systems, so that it can more readily become a daily transportation mode.... In general, the rationale for introducing bicycle-sharing is to promote cycling, increase mobility choices, improve air quality and reduce congestion. It is also seen as a means to promote the viability of public transport by providing an “extension service” for the “first/last mile” - the distance which many consider to be too far to walk between home and public transport and/or public transport and the workplace.'

That's why the bike is not equipped with a rack: it's not meant for grocery shopping or other utility use.