This lesson vs 'Using the conditional or the perfect conditional to express objection/disbelief'

Question

Why is the future/perfect future sometimes used for the same reason one could use conditional/perfect conditional?

Silvia Piriz · Accepted Answer

Hola Jessica H.
This is a great question. Although the forms look similar on the surface, they are not being used in exactly the same way.
When we use the future or perfect future to express objection or disbelief (e.g. ¡Será verdad! / ¡Habrá sido él!), we are usually reacting to something that has just been said. The future here doesn’t really refer to future time — it expresses doubt, surprise, or a kind of ironic distance from the statement.
The conditional or perfect conditional, on the other hand, is more typically used to soften a statement, express reported information, or show conjecture from a past perspective (e.g. Habría sido él = “It would have been him” / “Apparently it was him”). It often sounds less immediate and less emotional than the future used for objection.
So while both sets of tenses can overlap in expressing doubt or disbelief, the future tends to sound more direct and reactive, whereas the conditional often sounds more hypothetical, indirect, or reported.
We’ll take another look at the two lessons to see if we can clarify this distinction more explicitly, as you’re right that the overlap can be confusing.
Saludos
Silvia