Progressive Web Applications (PWAs) offer a plethora of benefits for ecommerce businesses. Firstly, PWAs provide a seamless user experience, combining the best features of both websites and native mobile apps, thereby increasing engagement and conversion rates. 

Secondly, pwa for ecommerce are highly responsive and load quickly even on slow internet connections, ensuring that customers can browse and make purchases without delays. Additionally, PWAs can be installed directly onto users' devices, eliminating the need for app store downloads and updates.

In terms of progressive web app development cost, PWAs generally require less investment compared to developing separate native apps for multiple platforms (iOS, Android). Since PWAs are built using web technologies like HTML, CSS, and JavaScript, developers can leverage existing skills and frameworks, reducing development time and costs. Furthermore, the maintenance costs for PWAs are lower as updates can be deployed instantly without going through app store approval processes.