Invest? You meant by buying those tourney tickets and watch to get the tourney drops? Or invest in betting games?

If you meant the former one then no point as people buy the tickets to support the tourney as well as to be able to watch it in Dota 2 game client. Tourney item drops are hard to come by unless you are very lucky or that tourney doesnt have much buyers. So investing is not encouraged.

If you meant the latter then its up to you to bet any matches.

orge? anyway,i am pretty sure joindota or reddiit will have tabs about the news, info, team participating, etc about a tournament...and if u mean by investing is to watch the games and hope for item drops, then u might want to think twice.
1st, its really hard to get items with good teams such as navi, alliance, etc participating in tournaments such as gleague, starladder,etc..
2nd, tournament items are really hard to sell nowadays for good price even with good tag...

only buy the ticket if u want to support the organizer or the teams that are playing in it...