After reading your email on the Android Gmail app, users can use "Mail swipe actions" to delete, archive, mark as read/mark as unread, snooze, mark as, and move to messages. Each swipe is a different color and each action is accompanied by a different color, but to make it even easier to tell the different gesture actions apart, Google has added some animation.
For example, mark as read will show the fold of an envelope closing. Delete an email and the trash can lid rises, and snoozing an email will spin the clock.
According to 9to5Mac, you should soon have the latest version of Gmail for Android installed on your phone. Google has been adding little things here and there in order to improve the app. For example, in February Google added confirmatory vibration feedback so that users don't make an accidental swipe on the wrong spot.
To make sure that your Gmail app is completely up to date, your Android phone should be running version 2021.03.07 which was released just last week. It is important for you to understand that the animations are not available on the iOS version of the app.
You can find the Gmail for Android app in the Google Play Store. These are small things that might not seem like a big deal but they are important to users.