IMO, I think there are good reasons for having this kind of throttling, but also situations where it would stand in the way of certain applications.
At 35K users, we're not yet seeing scale or any kind of high levels of noise and abuse. This could change rapidly in the 100-500K user range. I think this throttling is a smart, conservative way to begin to think about that.
On the other hand, it might prevent 3P apps from doing certain things which use the Steemit blockchain programmatically.
Edit: as per comments, this may impact value of posting only, not actual ability to post.
RE: Steem 0.12.0 Hardfork This Tuesday Will Bring Spamming Penalty If You Will Post More Than 4 Posts In 24 Hours