For the most part, alerts are posted with the STEP name of the failing step. Putting a validation in it's own step makes the alert nicely readable and easy to distinguish from other actions that may otherwise be in a step. I have not heard a compelling reason why this is a bad thing to do... I've been told it's not a best practice, but it's not been explained what exactly makes it a bad thing.
Answer by Nyna W. ·
This is not necessarily a bad practice. But just something we do not recommend.
Reasons mainly being:
1. It consumes XF measurements for that step even it only has one validation action. So instead of being charged as one step, with validation being another step, you are charged for two steps.
2. You will see a pause/blank line in waterfall for such step that does not have actual navigation or no objects downloaded. This causes confusion for a lot of users.
You are right that for script wise, using one step with multiple actions and the last one as validation, Vs using two steps with the validation action as the latter step, they are the same.
To fulfill what you want to do here with all actions being in one step, when the script fails with validation for that step , with the error type being Content Match Failure, you will still know it is validation failed not other actions.
To get more information from alerts, you can add the validation content with '-' as a separator in the step name. For example, for the Checkout step with Validation as 'Show in Cart', the step name can be changed to "Checkout page - Show in Cart".
Hope it helps.