Just imagine how easy and very fast it is to enter song with numbers instead of positioning note heads on ledger lines.

|1· 1· |1 23· | Row, row, row your boat
|1 1 5 5 |6 6 5 - | Twinkle, twinkle little star
|1 2 3 1 |1 2 3 1 | Frere Jacques
|5 3 5 - | 5 3 5 - | Barney "I Love You" (aka This Old Man)

Some advantages are :
1. Users do not need to know keys to start writing tunes for any voice range. Tunes written can be played back in any keys.
2. All tunes can be indexed and searched by their number pattern as can be seen above few examples.
3. Printed song sheets can be very compact without any ledger lines.
4. Basically all musics are patterns of notes which can be notated in numbers for fast analysis and learning. eg. notes in 1-3-5 pattern is root major chord.

BiaB is soon going into version 18 (or 2009). This feature could give a big break into the China region market as this number notation system is commonly used there.