Some developers no longer want to imply that Bitcoin offers cheap and fast transactions since a fee market will likely develop:
The current site text makes repeated mention of Bitcoin providing low transaction fees and instant transactions, as well as strongly implying that any transaction paying a fee or having medium priority will be confirmed in the next block.
As instant transactions can be unsafe and the other things are less likely to be true in as available block space becomes fully utilized, this pull removes or clarifies those sections.
Link with screenshots of proposed changes:
https://github.com/bitcoin-dot-org/bitcoin.org/pull/972