Data Value Changed vs Lead is Created + Constraint

[Anonymous]

We are monitoring for new leads coming into Salesforce from AppExchange. The catch is that we merge duplicate leads, but still want to send them an email when they come in. To Marketo, a merged lead will appear as an updated lead. I was thinking I'd use the Data Value Changed method to handle these leads, but wanted to know if Data Value Changed fires on new leads too.

Does Data Value Changed fire for new leads or just updates to existing leads?

[Josh_Hill13]

Data Value Changed is a filter, not a trigger.

Data Value Changes is a trigger. This will fire on new leads or anytime the selected field receives an update.

A better way to handle this situation is to say

Fills Out Form IS "x" on Page IS "Y"

to ensure the email is sent when the lead comes in. Of course, it might come in differently via AppExchange.

Another way to consider handling this is to use two Triggers because Triggers are always "OR" between them. An Example:

Data Value Changes IS "X"
OR
Lead Is Created Source IS "X"
OR
Fills Out Form IS ANY

[Anonymous]

I can't find the list of possible constraints or reasons for data changes trigger. I'm looking for values like due to form fill or manual change or by a flow step.