The strongest suit of Dota 2 is its depth. One can spend 1000 hours consecutively on it, but s/he can claim to be a master at it. Like you would be nowhere close.
Obviously, you're gaining experience here; you'll be learning more and more. Besides to the amount of content in the game itself, there is so much outside as well like Guides, Fan Art, Stats, Competitive Streams, Competitive Vods, Newbie Commentaries, Analysis, Fan Music, Fan Literature, News and Tournament Analysis.
If you plan to play it in a team, you can really have a social gathering of it. A team of 4 friends playing together is completely different experience than playing alone. If your team keeps on playing, it gives you more chances of staying in the game just because you like hanging out more with them.
Due to its features and true diversity, it has become most Addictive Game of this Generation on Online Platforms.
He is considered as a complete character because he can perform most of the roles in the game.
In most of the people's opinion, He is the best Hero cause he can be a killer, pusher, supporter, jungler and disabler too.
He's just so useful. Especially in full level and items.
Fan Arts are one of the reasons that shows the diversity and how people love to follow this game, many people are addicted to the game like people follow some movie series and seasons. Fan Arts always kept it alive.