Isn't annihilation? Really?
You take a cardboard box and burn it what is left...ashes...(Is it still a box) of course not! The box is gone.. What is left is the very basic material in which the box was originally made of...earth...just as man dies and he returns to dust...it is no longer a man or any resemblance of...just the matter from which he was originally made from....
so annihilation? Yes, he is gone... Mal 4:1 speaks of a time when all the wicked shall be no more..."For, behold, the day cometh, that shall burn as an oven; and all the proud, yes, and all that do wickedly, shall be stubble: and the day that comes shall burn them up, saith the Lord of hosts, that it shall leave them neither root nor branch."
A box when it is burned up has neither root nor branch as well..just ashes...just earth and nothing more...until that material is used to make something else....
Continue with verse 3 "And you shall tread down the wicked; for they shall be ashes under the soles of your feet in the day that I shall do this, saith the Lord of hosts."
So are they annihilated? Certainly...they will be no more...not even a resemblance...just a pile of matter that is earthly....
When a pile of trash, limbs, boards and other material are burned, do you know what they were...nope, because what they were is now just basic elements once again...