If you have Yes or No data to store in DB, what will you select as the data type? Most of the times you will select “Bit”. Because it only takes 1 bit to store data. And it is the best data type for this situation. But it takes more than bit in SQL Server. If you have only one bit column in your table it will allocate 7 more extra bits to store your bit data.
And if you have two bit typed fields in your table it will waste 6 more bytes. But if you are using 8 bit typed fields in your table, it will not waste any space. And if you have only one such a binary values column in your table. Otherwise it will take space same as char(1) or tinyint. Although its name is bit it is not small like bit always.