There's a good number of people saying this strike is meaningless and reddit's API change will only affect a tiny % of users. I want to explain why I believe they are wrong.

Engagement is a power curve. Most content is created by a small subset of users. I think it is a fair to say that if you use and especially pay for third party tools, whether that be a client or something like RES, you are more than likely a power user. If you moderate a subreddit, you're probably a power user. If those power users go away then you lose a large swath of content and moderation which negatively affects the regular users at other parts of the curve. It is not going to be immediate but this is reddit slowly bleeding itself to death.