Usually not. A film with a wider shape than the screen needs letterboxing if the full picture is preserved.
Why this happens
A widescreen television does not have the same shape as every film or older television programme. Keeping the whole image can leave black bars above and below a wide film, or at the sides of an older narrow programme. Those bars are not automatically unused bandwidth or missing picture quality. The meaningful question is whether faces and objects keep their normal proportions and whether the full composition remains visible. A forced full-screen image can remove the bars by stretching or cropping the content.
Try the player’s default aspect ratio before choosing a fill option. Compare a face, a circular object or a channel logo rather than judging only the empty area. Stretching changes shape; cropping discards part of the image. Neither creates extra original detail. If the bars are already encoded into a particular feed, some players may not distinguish them from the programme itself. A separate source version can help establish that. Choose the presentation you prefer, but keep its effect clear when discussing a picture-size problem.
A useful way to work through it
Select the normal or original aspect-ratio mode for the player.
Compare shape and edge detail before and after a fill or crop change.
If only one feed has unusual borders, compare its alternative version before changing the TV.