Not all bad
Seed has a place for some birds.
Updated
Bird guides
Seed-only diets are a problem for many pet birds because birds can pick fatty favorites and miss key nutrients. Seed is not automatically bad, but free-choice seed should not be the whole plan for most companion birds.
The issue is not seed existing. The issue is seed taking over the diet.

Food and Water
Seed-only diets are a problem for many pet birds because birds can pick fatty favorites and miss key nutrients. Seed is not automatically bad, but free-choice seed should not be the whole plan for most companion birds.
Transition without making the bird go hungry.
Use the hub for nearby questions after this answer.
Use supplies after the care plan is clear, not before.
Pick gear that makes the daily routine easier to repeat.
Seed has a place for some birds.
Seed-only is often unbalanced.
Birds pick favorites fast.
Change slowly enough that the bird eats.
Rich seeds add up.
Diet advice changes by bird type.
Many pet parrots need more than a bowl of seed. A seed-only routine often makes it hard to manage vitamins, minerals, weight, and picky eating.
Finches, canaries, doves, parrots, and lorikeets do not use the same diet plan. A diet that is normal for one bird can be wrong for another.
Birds often pick sunflower, millet, or rich pieces first and leave the rest. What is offered is not always what is eaten.
Do not pull seed suddenly from a bird that does not recognize the new food. Slow changes protect appetite and droppings.
Use seed deliberately inside a species-appropriate plan instead of letting seed become the plan.
No. The problem is relying on seed as the whole diet when the species needs more balance.
Budgies can eat seed as part of a plan, but many still benefit from greens, measured portions, and careful diet variety.
No. Sudden changes can make birds stop eating. Transition slowly and monitor intake.
New textures can be confusing. Offer pellets consistently, use small changes, and avoid starving the bird into acceptance.
Use these after the care plan is clear. Match size and materials to the bird you actually keep.
Affiliate links: Furball Cove may earn from qualifying purchases at no extra cost to you.

Keeps pellets and seed portions sealed, labeled, dry, and separate from treats.

Separate clean food and water dishes that are easy to wash every day.

Makes weight checks easier before small appetite changes become big problems.

Tracks food, weight, sleep, droppings, behavior, and vet questions in one place.