The first day is more of an observation and solemn day; rather quiet and due to its significance as the first day of the year; there's also typically more taboos and rules to follow on that day which will be out of the norm.
On the 2nd day however, everything resumes to normal where you can sweep and clean the house already:)
Also, most of the married daughters return home to their families for reunion; bringing their husbands and kids along.
Thus, Cantonese often term this day as Hoi Nin as in the real start of the new year and welcomes the new year:)
Granny herself is of Cantonese origin and thus she was also busy preparing for the 2nd day; lighting joss sticks to worship all the deities and pray for the entire family.