Database column suffixes

Why do you need suffixes describing the database type on the column name?
For instance: "amount_int" ? Why not just "amount" ?

We have a DB set up here with this archeticture, but the funniest (saddest?) thing is that the suffix is not always correct. So it doesn't really save any time because you have to look at the database to confirm anyway.

This brings me to my current project, which has me adding a new column to an existing table. The new column exists in another table, but is incorrectly suffixed as "_si" for small integer, but has been since changed to a full integer and should have been updated to "_int" but obviously wasn't. I guess it was too much of a hassle to update all of the coding that references it already.

This is EXACTLY why I think it is a bad idea to include this in the column name. So...in the new table I got the answer that we want it to be correct (use "_int".) Therefore the two columns which are storing identical information for the same purpose are named 2 different ways.

Bottom Line regarding using suffixes in this way:
Cons:
More to type when coding
Makes datatype changes either a huge project or makes the column name suffix incorrect which defeats the purpose

Pros:
Gives me something to type about here.