If you're happy to pay whatever it costs to host then there's no other disadvantage to this.
The only thing I can think of is if you somehow end up at odds with an admin of a big instance and they defederate your instance. Or perhaps in the future major instances decide to only federate with instances of a certain size, for some as of now unpredictable reason
Yeah an absolute bolt from the blue, how can New Zealand ever prepare for the sudden and unprecedented invasion of multistory buildings.
Saw a comment on my local councils post of someone worried that the Tauranga CBD would look like Shanghai in a fews years "at the rate they're going".
Some of the most popular, picturesque tourist spots and residential locales in the world make NZs "high density" plans look laughably wastaful in comparison, and people are still tearing their hair out about it.