I'm new and want to learn about Lone Druid's & Queen of Pain's pros & cons.

Hi. First, i'm sorry if this post kinda stupid or something, but i'm new to Dota 2 and on my way learning some of it's heroes. I've understand the basic concept, like roles, runes, cs, wards, and just played the games (vs bot & tutorial) for ~30 matches. A friend of me who introduce me to this game recommend me to go here on Dota 2 Reddit so i can ask some good advices, so i'll be straight and truly appreciate the community here.

So, for the first few games, i play Sven. He's good and simple. Later in All Pick game mode (vs bot), i try to play each hero once, and finally made my mind to focus on Lone Druid (i chose him mainly because i'm a fan of that classes in WoW) and Queen of Pain (again, it's only because she resembles Fairy Tail's Mirajane devil form) first for some of my games. That friend of mine told me that both heroes are not suitable for beginners, and he said that both also one of the most popular heroes in professional level. With that said, i begin to think, a hero with only normal attacks (Lone Druid) and a teleportation skill (Queen of Pain), how can they popular in professional games? What are their strength and pros? I'm sorry if my words a bit harsh to their hero user, but really, i really like them and just want to know more, thank you. :)