BAM already allowed line numbers to have leading zeroes.
This can be useful to make line numbers stand out a little by having them all a consistent length.
Leading zeroes, though, can be a little bit annoying when having to type those leading zeroes in GOTO and GOSUB statements, and BAM previously required line numbers with leading zeroes to have those leading zeroes in GOTO and GOSUB statements.
For example:
00012 PRINT "HELLO"
GOTO 00012 ' exactly matching line number required
GOTO 12 ' this fails because it is not an exact match
' by the way, this allowed the following two line numbers to coexist and be treated as unique: 12, 012, 0012, 00012, etc.
' that may be convenient for some folk, but it can be ridiculously confusing for others
Now, BAM ignores leading zeroes in line numbers, so:
00012 PRINT "HELLO"
GOTO 00012 ' this continues to work
GOTO 12 ' now this also works
' of course, this now means that the following are no longer allowed to coexist because they are no longer unique: 12, 012, 0012, 00012, etc.