Your statement is a PoS history has no verifiable longest chain , actually it is the same as PoW , in that the Longest Chain with the most difficulty wins and normally will be the true chain.
Checkpoints are not verifiable math. They are adhoc social trust. The entire point is that PoS is not trustless, because nothing can be verified about time with math. Please go back and re-read the OP, because you've not understood the OP.
This make no sense , every Block has a time mark , PoS or PoW .Nope. See what I wrote above.
A properly designed PoW block chain with sufficient hashrate doesn't need checkpoints.
Also a properly designed PoS block chain with sufficient difficulty doesn't need checkpoints.Proof-of-Stake "Wastes" More Resources than Proof-of-Work
Hopefully I have justified to why I refer to PoS as P(iece)o(f)S(hit).
You are not factoring in the cost of bribing the stake and other strategies that must occur because PoS is a power vacuum due to the lack of mathematically verifiable time. You did not read carefully the OP and the links provided which elaborate in great detail. Go click all the links in the OP, because you are entirely incorrect.
Your ignorance (and being too lazy to read all the links) is not a valid rebuttal.
Again , you will need to explain this , as it seems to be rambling.