I'm not as streak fanatic as @brandonwilson , but you make the time for the things you care about. Simple as that.
You can still write every day without a streak marking the days.
I'm going to launch myself on a tangent that I feel it's still relevant to 200WaD though.
I've been working on multiple tasks every day since November. I did not have a single totally unproductive day weekends included. Hell, I even wrote an article for Christmas day while dining (in Italy we usually have a 5+ hours lunch on Christmas day).
I'm just not logging my tasks on any task tracking platform, I find them a waste of my time. I'm not being productive by logging what I already did into yet another platform. Before coming to this conclusion I tried them a few times though, never assume anything before trying it on your skin.
A different thing is if the platform encourages you to create something as 200WaD does. It does not ask you to log how many words you've written every day. It asks you to write.
I find that to be the key difference between 200WaD and all other platforms. With other platforms I found myself going there often just to procrastinate doing actual work. The cure had become the disease. Distraction masked into productivity. The bad thing about it is that you think you're being productive, but you really aren't.
This is my opinion based on what works and doesn't work for me. I've heard from many people that for them is an encouragement to work and create. If that's you great! I wish it was the same for me as well.
If you get something out of it, anything, even just the will of creating more because of the accountability, it is not wasted time. For me, it just distracted me from actually doing the task.