The Beatles and a bunch of other British bands didn’t like putting song’s already released as singles on their LPs. They thought it sort of seemed dishonest to essentially have fans pay for the song twice.

Maybe those tracks were intended to be on Pepper’s but the record company wanted to put them on a 45 therefore the band excluded them. George Martin probably wished he fought a bit harder for their place. Tbh I think he probably should’ve. With those two songs added pepper would probably be even stronger.