After playing for a long time on Taylor guitar, I think I am closer to the reason why Cheer play in - 2 semitones from the regular tuning of EADGBE and capo back at Fret 2 to make it in standard tuning.
There are a few possible reasons; technically & musically:
a) It is easier to barre chord by capo at Fret 2 for standard tuning song.
b) For smaller hand (subjective, and not referring to Cheer or Tiger's left hand) like myself, you can do barre chord of say, a F major and at the same time extend your pinky finger to the 5th frets and letting it ring throughout (i'm referring to A Yue's 思念是一種病 distinctive 4 notes riffs comping). It is difficult to get the same effect if you use standard tuning to the actual 5fret (it is has a longer distance ...frets get nearer to each other as it goes down the neck)
What you may lose it the open ringing sound as your guitar strings is effectively shorter
c) You can have the flexibility now to sing and compose songs -1 or -2 semitones from regular tuning.
Some example :
路口 (by 張震嶽) is using -1 semitone from regular tuning
吉他手 (by Cheer Chen) is using -2 semitone from regular tuning
我親愛的偏執狂 (by Cheer Chen) is in regular tuning by Capo at Fret 2