Steem is different than most other cryptocurrencies as most of its inflation doesn't go to pay for the security of the network but to the content creator.
Linear reward introduced a loophole which was explained in the original whitepaper. We talked about this at length already so I'll leave it to this.
This loophole gives the possibility for opportunists to extract a growing amount of value for a negligeable amount of work. This is at the expense of the whole network value.
RE: HF21: What Makes Steem Valuable?