Yes, we always recommend an expansion joint of 5 mm on all sides so that your floor can expand and shrink as the temperature changes. You can install the floor over an area of 20 m width and 20 m length without discontinuations. In principle, discontinuations between different rooms (profiles) are not needed if the total length is no more than 20 linear metres. Unless there are significant differences in temperature between rooms, it would be better to install a profile.
Do not use (flexible) silicone to seal the expansion joint! Use the accompanying profiles and skirtings to finish the area neatly.
Want to know more about laying a Floorify floor over a large area? Read: Can you lay the floor without profiles?