Independent games lean heavily on pixel art, and the usual explanation is affection for older consoles. The stronger reason is production capacity, because art is where small teams run out of time.
Art is the largest and least compressible cost
Code can be reused, systems can be extended and levels can be built from existing parts, but every new character, prop and environment needs someone to draw it.
A team of three has perhaps one artist. That single person sets the ceiling on how much the game can contain, regardless of how ambitious the design document is.
Choosing a style is therefore a choice about throughput. The question a small studio has to answer is how many finished assets one person can produce in a year.
A low resolution puts a hard limit on detail
A sprite drawn at a small pixel size cannot absorb infinite refinement. Once every pixel is placed, the artist is finished, because there is nowhere left to add detail.
Higher-fidelity styles have no such stopping point. A hand-painted character can always be improved, and without a limit the work expands to fill whatever schedule remains.
The constraint is what makes the estimate reliable. A producer can look at a sprite sheet and know roughly how long the next fifty assets will take.
Animation is where the savings actually appear
Static images are only part of the cost. A character needs to walk, turn, attack, take damage and die, and each of those is a sequence rather than a picture.
Pixel animation can carry a convincing motion in a handful of frames, because the viewer's eye fills in what the resolution omits.
Three-dimensional characters need rigs, weight painting and motion work before a single animation exists, and each of those steps requires a different specialist.
Readability improves rather than suffers
Small canvases force strong silhouettes and limited palettes, both of which make objects easy to identify quickly, which matters in fast games.
An enemy that reads clearly at a glance is a design asset. Detailed art can obscure what a player needs to see, particularly in a crowded scene.
This is why the style survives in genres where speed of recognition decides outcomes, rather than only in games that are deliberately retro.
The style carries costs of its own
Pixel art has become common enough that it no longer distinguishes a game on a storefront, and a shop page full of similar thumbnails helps nobody.
It is also unforgiving. Bad pixel art is obvious, because errors sit on a grid where the eye finds them, and mixing resolutions looks careless immediately.
Some studios respond by combining the style with modern lighting or camera work, keeping the production savings while avoiding a look the audience has already seen.