I know what I'm asking for, is now already doable in Vegas Pro 20 by using Selectively Paste Event Attributes, which is already a great step forward!
Currently, the effects in the effects panel can only be indicated, made visible and invisible, movable between each other and are removeable by a button on the effect panel.
It would yet be easier if in the effects panel we could just copy one or more effects with its animation, paste, cut from one video to another video or delete effects by using its shortkeys : CTRL-c, CTRL-v, CTRL-x and with the DEL-button on the keyboard.
But as I said, using the Selectivety Paste Event Attributes in Vegas Pro 20 is already a big step forward! Thanks for that.