Improved productivity's first and foremost beneficiary is the profit that the business attains. Higher profits means the firm can afford to pay more wages to its workers and this results in higher spending power of these workers. Higher productivity may also result in consumers' price fall or stability (assuming that the production cost stays more or less the same), then result in price control. Higher profits and productivity also means that the firm can invest larger amounts and, using the goodwill generated, can also seek higher loans. The scenario may also motivate the firm to enter international markets and leverage their productivity and lower cost to scale up the business.
All this, in turn, benefits the society. A part of society, the workers, will directly benefit from higher wages and will be able to spend more. This will benefit the vendors and society as a whole. If the firm invests to scale up their operation (whether for domestic or international market), the region will benefit from additional employment generated. Not only direct, but indirect employment will also be generated (think of all the people whose livelihood is dependent on these additional workers). A bigger industry will also ensure better infrastructural facilities for its employees and neighboring region, in terms of better schools, medical care, roads, communication, etc. Thus, improved productivity will be a big boon for the society.
Hope this helps.