does naming files with underscore/dash matter? (My Library, Macros & Rollable Tables)

I know very little of API, so my interest is in the free acount and I was curious about if the names of the files really did matter? I experienced that if I import a picture from my desktop named "My Picture" it will be uploaded to "my picture.jpg (or png)". Knowing little about any kind of scripting I learned to name files with "_" (underscore) but my generel impression is that Roll20 replaces all "spaces" with a dash (-). Q1) Should I worry about how I name my uploaded files? Q2) Is there a reason why people always name their Rollable Tables with "dashes" instead of "underscores"? Q3) I have created several folders in "My Library" to stay organized with my uploads, but if I change the name on the file located in my self-created folders it does not change the name of the uploaded-file (I can see that by clicking the interlocking squares next to the "Recent Uploads") - how much does this matter? I'm sorry if the question doesn't make sense, it's just difficult for me to figure out if I should continue naming files with "underscore" instead of "space".

A1) nope. The url for a file, which is what the API uses, as no relationship to the source file name.  A2) the interface turns spades into dashes.  A3) that sounds strange but probably isn't something to be concerned about. 

Would you recommend naming my files with dashes or underscores for practice? in case I want to tinker with API or any other scripting?

You don't need to use any special naming. Whatever their name is is what they will be labeled with in your library. To the API, they'll have a generated url that is unique and not something you have to worry about. It will just be a hash of numbers and letter, not based on your file name. You could name all your images "bob.png" and it would make zero difference to the API. 

Thank you for quick reply The Aaron :-)

No problem!