Well, typically you're very dependent on going to land for supplies. Water, food, fuel. The seastead philosophy is more sustainable for a closed ecosystem by being large enough I assume to grow food, collect water, harvest solar, have a social life or job.
I do keep the boat in a marina right now yes, for the convenience of land access. It has power, water, showers and bathrooms and parking for myself and visitors.
Even at a marina, it can be a struggle, everything in your life takes more effort and the boat is always needing something. But it's a struggle I enjoy, to be in touch with the weather, tides and animals, I don't have additional pressure of high rents stealing from my productivity, I can throw the lines and leave anytime with my entire 'house'. The marina is the good middle-ground for me though, the thing I tend to miss the most when I'm out on the water for long periods is social interaction.