I am in favour of activating Segregated Witness (SegWit), but I am no more an authority than anyone else. Make up your own mind.
Here is why I think SegWit should be activated: it solves a number of different problems and is the best-tested solution that exists. I used to think that big blocks would be better; I've run Bitcoin Classic, XT, and Unlimited to evaluate the software and understand how they work. The problem with Unlimited is that it doesn't change the rules -- it sets the rulers, who will get to change the rules.
That is a very dangerous thing to do in Bitcoin, and Unlimited is also an untested system of consensus. Bitcoin will be attacked eventually; maybe it's better that it's sooner rather than later. Hard-forking Bitcoin without very broad consensus will hurt investment in this space as a whole. But for those who use it as a currency, it still works whether the price is $20 or $200 or $2,000.
Transcript
[AUDIENCE] A question from the community: SegWit versus Bitcoin Unlimited. What is your opinion on it? [ANDREAS] This is kind of a really difficult, but at the same time fairly easy, question. I am in favor of activating SegWit now.
[Applause] The reason for that, and don't applaud... [Laughter] Form your own damn opinion. I am no more the authority you should listen to than anyone else; this is not a belief system where I say: "FC Barcelona!" and you [shout], "Yeeeaah!!" Make up your own mind. I'll tell you why I think it's true.
I think SegWit should be activated now because it solves a number of different problems. Its the best-tested solution that exists. I will make a disclosure: I used to think bigger blocks would be better, about two years ago. I ran Bitcoin Classic, XT, and Unlimited to evaluate them; not because I thought we should hard fork to those, but to evaluate the software and understand how it works.
If the choice was SegWit versus Classic, I might say, '[In a year], we could also do [a block size increase].' The problem with Unlimited, in my opinion, is that it doesn't change the rules, it sets the rulers... who then get to change the rules. That is a very dangerous thing to do in Bitcoin, especially if it is done as a contentious hard fork. I think Bitcoin Unlimited is a completely untested system of consensus.
If somebody wants to test that with 51%, it [will] be an interesting experiment. Bitcoin is going to get attacked eventually. Maybe it is better if it gets attacked sooner, rather than later. If you hold bitcoin as an investment, this will be painful.
Hard-forking Bitcoin, with a low percentage [of the hashrate] and without very broad consensus, will damage Bitcoin. We will end up with two chains that survive, and the sum of their value will be less than [with just one]. I think that's a very bad idea, [but] not my choice [alone]. Here is something I can tell you: bitcoin as a currency, as a means of exchange, for getting paid in my job, works at $200, at $2,000 dollars, and at $20.
It doesn't change for me. Bitcoin as a stable store of value, however, doesn't work with a hard fork. It depends on what you use it for. There is probably a broader discussion to be had there.