Multi acts as both the Defense and Stamina user of this series, rather than specializing in just one. Defense and Stamina commonly used together in hybrid builds, and generally have a similar playstyle. Considering that she's also a Bey Crafter, she's probably tinkered around for her ideal style.
In addition, as a streamer, she would want to mix things up to ensure peak entertainment.
Team Phalanx's Stone Wall strategy is often soured on due to how boring and predictable these matches are. In a last bey spinning scenario, they will often just bore an audience over 3 to 5 rounds depending on if it's elimination or team fights. But remember that Beyblade X's standard format is a first to 4 points. Spin/Survivor Finishes are ONLY 1 point each. Unless they manage to score an Over/Ring Out or a Burst Finish which is 2 points each, this is their primary win condition. Now spread that out to two to three players and those boring matches start becoming snooze fests.
Bird losing all of his battles makes sense when you remember that he was an amateur who only became a pro because Ekusu formed a team with him and won against Team Phalanx in the amateur tournament, instantly moving them up to the finals where he defeated Multi. This means that Bird never got to battle others in his weight class and losing out on gaining experience that would have helped him improve earlier on. Not helping matters is that after his primary bey was destroyed, he has to use a new one that he’s unfamiliar with.
