The G Pay app isn't the same as Google Pay. G Pay is an older version that doesn't include the Insights feature. It's installed on many devices from 2021 and earlier by default. However, if you want all the features, it's better to upgrade to Google Pay.
Google Pay combines Android Pay and features of Google Wallet to let you send payments to friends, pay in stores, and manage your finances.
If you have the older version of Google Pay from 2021, update it in order to see the new features.