“It’ll have to be insulated otherwise the liquid will evaporate and depending on the construction of the tank, a high pressure may develop.”
Technically, it's already under high pressure, CO2 can't be liquid unless it's kept at greater than 5 atmospheres. Sorry, being pedantic🙂
A CO2 system also needs to warn people to leave before it activates, it'll asphyxiate them at lower a concentration than is needed to put out a fire. Using it in a club could be dangerous, if they don't hear the warning due to loud music.
https://blog.koorsen.com/what-is-a-co2-fire-suppression-system-and-how-does-it-work