No. You are still required to download and register the Touch 'n Go eWallet account.
The MYTouchnGo Portal only manages your Touch ‘n Go cards while the Touch 'n Go eWallet is an eWallet that allows you to make payments and more via the mobile app.
Below are related articles that might be useful for you :
What can I do with my Touch 'n Go eWallet?
Are the features available to all Touch 'n Go eWallet users?
Does this mean I do not have to use the Touch ‘n Go Card to pay tolls, transit fares, etc.?