In general any new software release should be “better” than its predecessor, But how exactly better and what are the differences.
Picture in Picture -
Android Oreo allows activities to launch in picture-in-picture (Pip) mode. This is a special type of multi-window mode which is mostly
used for video playback.Now you can more effectively multitask while you are working on your daily basis.
When Pip mode is active, the floating video window can be dragged around the screen, but it always sticks to the closest edge of the screen. The video is small, but it's borderless, and the controls are hidden to save space. You can tap on the video to get playback controls, as well as buttons to return to the full-screen app and an "x" to close the video immediately.
Autofill Framework -
It is designed to make filling out forms, such as login and credit card forms, much faster and easier. Developers can optimize their apps for Autofill by providing hints to what a given field should contain as well as marking which fields are important for Autofill. With Android Oreo, completing forms and passwords just got a whole lot easier.
Wifi Aware -
Devices with the right hardware can discover and connect directly to each other via Wi-Fi Aware. These networks are made of clusters of neighboring devices.Android Oreo supports the mechanism for finding other devices in the vicinity as well as the ability to create a bi-directional Wi-Fi Aware network connection, all without using a “traditional” Wi-Fi access point.
NO default maximum aspect ratio -
Apps for Android 7.1 or lower have a default maximum screen aspect ratio of 1.86:1.With Android appearing on more and more different non-mobile type of devices, plus the recent experimentation by handsets to shun the traditional screen ratios, this change offers more freedom to device makers.
Limiting Background Programs -
Foreground apps can be battery killers, but that is OK, as the user has made a conscious choice to play a 3D game or watch a movie and is expecting a related drop in the battery level. However, background tasks can be more insidious. Since they are not interacting with the user, the user has little or no knowledge of what these apps are doing and how much they are draining the battery.
To try to limit the damage that background apps can do to the battery level, Android 8.0 Oreo implements background execution limits, a mechanism which limits certain behaviors by apps that are not running in the foreground.
Bluetooth 5 -
Bluetooth 5 extends and enhances the Bluetooth Low Energy aspects of Bluetooth, it does not alter Bluetooth Classic. Bluetooth 5 offers greater speed and distance for Bluetooth Low Energy connections but these are mutually exclusive, you either have greater speed or greater range, not both.
To wrap up the Android 8.0 Oreo is definitely better than Andriod 7.0, But some features which comes exclusively for Android 8.0 cannot be utilized by already released devices which are just receiving just an software upgrade.