How would you rather buy them? In or out of the packet..
I'd rather get them in the packet although have some in and some out in my collection.
Keep them in the packets as you can still see the card. If you never want to sell them then take them out of the packet as they will look better.
If never wanting to part with (if I had Raiders ones I wouldn't be) I'd open them. But if unsure then yeah keep them in plastic especially if they still fit in sleeaves like that