411A
I would only divert in the circumstances you describe IF
the destination airfield could not give me an EAT due to unknown delays - blocked runway for example
or
the EAT was too long to wait (happened to me last week)
Going to an alternate say 20 mins away, when you have an EAT in 10 mins or so, puts you in a far worse position on arrival at the alternate then you would have when approaching destination at the EAT.
You could well have enough in the tanks for another go if it all goes pear-shaped!
As for long haul over-flying alternates knowingthey will be short on arrival - there's a bit more to think about I reckon.