Why does Button[] not work with SystemDialogInput["FileSave"]?

Questions
1

datalist = {{1, 2}, {2, 4}, {3, 8}, {4, 16}};

Button[“Save”,
Export[SystemDialogInput[“FileSave”], datalist, “Table”]]

After I run it, I can see the filename but cannot find it as a file. Thanks.

2

It seems that without Method->"Queued" Export will not wait for your choice. Use it then:

Button["Save", 
 Export[SystemDialogInput["FileSave"], datalist, "Table"], 
 Method -> "Queued"]
3

It works. Thank you.