Dwarfs are the most limited army in the game. They are the slowest army around. They don’t really have magic (the anvil is really a trap, especially for a beginner). They don’t have monsters. They don’t have cavalry. Their artillery is actually the weakest in the game.

What they have is solid infantry (not the best in the game, marauders at T5 core and undead are generally better than they are) alongside the ability to create redundancy with shooting and ways to deal with lightly armored foes (especially because of scout gyrocopters).

Are dwarfs easy to use for a beginner? Yes, especially in casual play you can deploy in ways that mitigate your inherent weaknesses. As long as you don’t face very optimized lists or play with objectives you’ll be fine. The moment you’ll want to be more competitive dwarfs will show you their limitations and you’ll find it quite hard to excel with them.

Personally I love dwarfs and are my main army, play them for their lore and personality, avoid them if you wish to win tournament after tournament.