For years now, power users have created solutions using Access Services within SharePoint. These solutions have often been the backbone of many business processes for small to medium-sized organizations. Now that Office 365 is widely available and is fairly cost-effective for those organizations, we have new options to solve those business needs.
Microsoft PowerApps is a new member of the Office 365 family and now that PowerApps is generally available within Office 365, Microsoft is recommending to organizations that solutions built with Access Services be migrated to the PowerApps service.
Access Services & Access Web Apps shipped with SharePoint 2016 and will continue being supported as part of the SharePoint product life-cycle.
Moving forward, information workers should build their apps using PowerApps on top of SharePoint lists to give the feature-rich solutions their users need with the full on-going support of Microsoft and the tech community.