EIP-1559 introduces the concept of block elasticity -- a temporary springiness to the size of blocks based on demand.
On Ethereum, this is set to 2x, meanining that a block can expand by twice it's traget size during period of demand, and the transaction fees can be smoothed out once this demand spike passes. It is a key piece of 1559, improving UX by allowing for more predictable
It does not affect overall bloat or transaction throughput.
Another side effect is that it allows for really big transactions to be published that otherwise are greater than the target block size. This can be useful in certain very complex contract deployments.
It's important that Ehtereum Classic does not get left behind when it comes to deploying these complex transactoins, and since ETC has a smaller target block gas limit (8M), it is worth considering if we cna increase the block elasticity to enable this use case.