Tooltip and SetAlpha

[Kindosar]

Hello, I'm very new to creating scripts in an addon format. I'm not new to simply writing them. I created an account because I cannot find this information online, so I'm hoping the pros here can help.

I'm trying to write a script that sets the opacity of the tooltip to be 0.5. When I test it (while mousing over something and typing the script directly into the chat window), it works; however, as soon as I move away from the object I'm mousing over, it returns to be 100% opacity. Here is how I write the script in game:

GameTooltip:SetAlpha(0.5)

If I put this into my addon, it changes nothing, however when I put GameTooltip:SetScale(0.8) into the addon, it permanently changes the size of the tooltip without issue.

Can you explain why this is happening and what I can do to fix this issue?

Thank you in advance.