SSMS Generated Table Scripts
1. Why is there a difference?

Simply because different code within SSMS generates the script differently. The SSMS GUI is well-known for being inconsistent (and broken in places). It's quite likely the features were just implemented by different developers or teams.
A more definitive answer would involve call to Microsoft Support.

2. Does it matter?

No, it doesn't matter.
SSMS added square brackets around the column and table names, so the script will work in cases where users named tables or columns using, for example, reserved keywords or spaces.
The result is semantically identical albeit inconsistent. SQL Server Books Online states the default float precision is 53:
float and real (Transact-SQL)
From that link:

float [ ( n ) ]
Where n is the number of bits that are used to store the mantissa of the float number in scientific notation and, therefore, dictates the precision and storage size. If n is specified, it must be a value between 1 and 53. The default value of n is 53.