⭐ Merited by vapourminer (1)
More transactions in blocks = more profit for every miner, no exceptions. If a bribed pool drops a standard transaction to make room for an OP_RETURN transaction, that standard transaction doesn’t just vanish -- another miner will pick it up. So the overall mining revenue increases with more transactions, regardless of type.
Of course, but I meant another issue (already mentioned by @gmaxwell if I remember correctly): Only the big miners/pools will have significant extra income due to Slipstream-style bribing. Thus the big pools offering such services will be able to increase their advantage over small pools and solo miners.The "difficulty increase" may happen because the big miners earn extra $$$, and thus can buy more hardware. And thus, the profitability margin for miners who connect to smaller pools, and solo miners, gets smaller, and some of them may get "priced out".
Clarification: I've written in the earlier post that "smaller miners" get priced out, this is incorrect. It's the miners in the smaller pools and solo miners, which is a small but important difference. I'm correcting that in the other post too
You would think a pool like Luke’s Ocean, which bans all sorts of transactions (and as a result earns less, ignoring variance and fees), would be irrelevant by now. But nope -- they've managed to gather nearly 6 EH of hashrate and are still growing!. That tells you there are plenty of miners who don’t want their hashpower used to mine what they consider spam.
This is interesting, but as long as the miners/pools who do accept bribes exist, the miners connecting to such pools will have a disadvantage, and some few may just fall below their minimum profitability margin due to that. I guess the effect is small, as already wrote, but it's at least ethically questionable, even if the centralization effect is very limited. It would be interesting though to know about estimations of the amount of this extra income -- just to know if there's a problem or not.