lol, it would cost more to send out the transactions than they are worth 
Fair enough but there is also no point in sending a 2 sat/byte transaction when there is 70Mb ahead of it in the queue and then telling your customers that the withdrawal is "Completed". That just causes masses of unnecessary support work for the sites receiving those transactions.
the problem is that because of the severely restricted block size on the bitcoin blockchain there just isn't enough space in the blocks for all the transactions at busy times like last week
if coinpot decided to pay hundreds of dollars to push their transaction to the front of the queue then it just means other lower fee transactions will suffer - ultimately causing someone else the "unneccesary" support work that you mentioned.
i think coinpot rightly stood their ground and say...hey our transactions are obviously not highest priority so we will broadcast them onto the blockchain so there is proof the withdrawal is completed and wait until the backlog clears for them to be confirmed on the blockchain
this is what happened within hours of my post - and i received my pending withdrawal along with everyone else - no big drama
this also means they avoid overpaying fees which would only end up being passed on to the user. so they can afford to keep their blockchain withdrawals fee-free (to me the user!).
tbh i might consider converting in the future and only doing my withdrawals with bch or dash as those coins dont suffer these kind of backlogs
I am fully aware of supply and demand on the blockchain. My point is that sending out transactions at 2 sat/byte when there is 90Mb of data ahead of them in the queue is pointless. Then telling customers that their withdrawal is "Completed" is misleading and causes many of them to then raise a support ticket at the receiving site.
They should simply tell their customers the truth. That is that they are unwilling to pay the current fees and their withdrawals will be delayed until the mempool clears out and then offer the option for the customer to pay the fee for a quick withdrawal.