Trello does one thing. Cards move across columns. You can teach it to anyone in two minutes, and the free tier is genuinely usable with unlimited cards and up to ten boards per workspace.
For a small team that needs to see who is doing what this week, that is often all that is required, and there is a strong argument that a simple tool everyone uses beats a capable one half the team ignores.
What it will not do
Dependencies, resource management, portfolio views, and any real reporting. There is no native time tracking. Once a project has more than roughly fifty active cards the board becomes hard to read. Anything resembling programme management will need something else.
Power-Ups extend it, and the ecosystem is large, but bolting five Power-Ups onto Trello to make it behave like Asana produces something more fragile and often more expensive than just buying Asana.
Pricing
Billed in dollars per user per month. The free tier is real. The Standard tier removes the board limit and adds advanced checklists and custom fields, which is usually enough. Premium adds the alternative views that other tools include by default.
Who should buy it
Small teams, simple workflows, and anyone whose current system is a WhatsApp group. Also excellent as a personal or single team board alongside a heavier system used by the wider organisation. Teams running complex, dependency heavy projects should look elsewhere.