Imagine a miner mines a block full of transactions, and those transactions paid a total of 3.5 BTC in transaction fees.
Imagine that miner sets his block reward to 25 BTC (instead of 28.5 BTC).
Couldn't you say that the 25 BTC block subsidy was created, and that 3.5 BTC in fees were mined out of existence?
The coins did exist. They were used as transaction fees. They were destroyed.
You could still argue about whether they just took the block reward, or accepted the fees and created under 25 BTC.
If you accept 0BTC for a block (0 from fees and 0 from your reward of 25), then obviously yes, the coins used as fees cease to exist, but if they accept at least as much as the fees it's pointless to try to decide whether they were accepting from the fees or from the reward.