Motel check-ins are not a recurring thing for most homeless people. They can't afford it because they aren't out there due to imagining that sleeping in a tent is some clever life hack that will save them money. But if you have enough income where it is feasible to spend $3000/mo on housing (that is more than I live on all month, supporting a family of three) and you imagine that sleeping in a tent on the city sidewalk will save you $3000/mo, that is just not realistic.
When the storms come, you will say "Fuck it! I am not sleeping in this! I am checking into a hotel. I can afford it for one night."
As soon as I had enough resources to check into a hotel periodically, my highest priority was being in a hotel during life threatening storms. It was often a financial hardship that I stressed about, but I did it anyway. So, I think the odds are really poor you will willingly subject yourself to sleeping outside in a bad storm as a matter of course if you don't absolutely have to.
I wasn't in Seattle. I was someplace a lot drier. Given how much rain Seattle gets, hotel stays on stormy days could easily exceed $3000/mo. On a per night basis, hotels are usually much more expensive than housing.
Additionally, you will not be welcome at homeless services. Those are aimed at helping poor people, not clever hippies giving the middle finger to society to save a few bucks. And people will likely be much less tolerant of you setting up a tent on the sidewalk than of actual destitute people doing so. If the neighbors and cops figure out you are adding to the homeless problem in spite of being able to afford housing, you may find yourself subject to a campaign of harassment until you either go elsewhere or relent and get back into housing.
If you want to save a few bucks, a better plan is to do some research and look for a cheaper housing arrangement. This might involve getting a roommate or moving to a cheaper town and commuting or something else that adds inconvenience to your life. If you can't tolerate those inconveniences, you really don't want the hassle involved in living in a tent with no plumbing, no electricity, no means to secure your possessions, etc.
Also, I don't imagine they will shadow ban you for asking a naive question in good faith. I don't think that violates any rules here. ;-)