Why it doesn't declare a winner
Weighing pros against cons depends on what matters most to you, which this tool has no way to know. Instead it cleanly formats the points you list into a side-by-side comparison with a simple count, leaving the actual judgment call where it belongs - with you.
Why this doesn't actually generate any pros or cons despite the tool's name
Unlike a tool that would suggest arguments for or against a decision, this one strictly formats the points you already bring to it - a deliberate choice, since the whole value of a pros-and-cons list comes from it genuinely reflecting your own reasoning about a decision only you are actually facing, not generic arguments a tool guessed might apply.
Why a simple pro/con count is shown instead of a weighted score
Treating every pro and con as equally weighted would be misleading, since in reality a single major consideration often outweighs several minor ones - showing just the raw count, rather than pretending to calculate which side "wins," keeps the tool from implying a false precision about a judgment that only you can actually make.
Why this is useful even though it does so little
Simply formatting a messy list into two clean, aligned columns - with inconsistent bullet styles and capitalization cleaned up automatically - makes a decision noticeably easier to actually look at and discuss, even without any analysis added on top, which is often all that's needed to think more clearly about a decision you're already most of the way through weighing yourself.