NA players can't play against BR teams because of the ping (BR can play against LATAM). All the franchise teams are in NA.
European players can play on almost all servers. All the franchise teams are in Germany.
APAC players can play on almost all servers (for example JP/KR can play each other). All franchise teams are in Korea.
NA teams will be WAY more prepared to face T2 teams from BR/LATAM that they compare against in Ascension and do you know what Riot answered: "we expect that teams from Franchise when they go back home they practice against the T2 teams in their region"... LOUD is in vocation and most teams as well, the time that the teams go back to their region is usually at the end of the year when teams are changing.