Some games use them when there's land scarcity (see ArcheAge for example) and to have a way to clear out inactive players. In ArcheAge, taxes are needed so the limtied overworld land is not occupied nonstop by people who maybe have left the game for a few months or years now, and the land is very limited there. This of course would not be an issue with an instanced housing system, because your house is linked to your account like a transmog/appearance collection is. It depends what direction the devs want to take it, but do expect taxes or one method or another to clean the overworld housing if there are limited plots of land or areas to fill.
Some games use them when there's land scarcity (see ArcheAge for example) and to have a way to clear out inactive players. In ArcheAge, taxes are needed so the limtied overworld land is not occupied nonstop by people who maybe have left the game for a few months or years now, and the land is very limited there. This of course would not be an issue with an instanced housing system, because your house is linked to your account like a transmog/appearance collection is. It depends what direction the devs want to take it, but do expect taxes or one method or another to clean the overworld housing if there are limited plots of land or areas to fill.
Decay timers solve this issue without making players grind out gold. I understand the need for gold sinks, but taxes are just bad taste.
Maybe a small tax just to keep the land open for the active player population.