Some shopping malls are just too cheapskate. They don't provide trash bins and benches (or insufficiently) for visitors. I can only guess that the reason for no trash bin is due to lowering the maintenance cost.
However, I can't think of the reason for not providing benches for visitors to rest within the mall. My guess is as wild as can be, e.g. could it be that more seated visitors would translate to less purchases? Or could the missing benches be motivated by the association that tired visitors tend to patronize eateries, cafes and restaurants in order to rest their tired legs (and hence more businesses)? Or could the missing benches be due to noncompliance to fire safety regulation? What do you think?
Sigh, I pity the visitors who might need benches to rest in these places, e.g. the elderly, expectant moms, and "mobility-challenged" (weight-challenged or wearing medical-cast).
Fortunately, all is not lost though, because visitors can still try to find salvage by locating staircases within the shopping malls. Once found, it will relief your tired legs. Not long ago while I was at a shopping mall, I noticed that some visitors indeed resorted to resting their legs at such places (i.e. staircase). I had done that myself and at the same time I have seen expectant moms with kids doing the same there. There are also the elderly patronizing the free resting "station". Some youngsters got food from stalls inside the mall (those without table and chair type) and just sat there munching away.
This is how sad visitors like us had to bear in shopping malls without (or insufficient) benches.
Just to share.