Reasons to try hard early in the game and hold on to your points:
* You have more points, which makes you harder to take out later on
* You have a chance at earning win streak gold
Reasons to **try to do badly** early in the game so you lose points:
* You get first picks in the draft
* You have a chance at earning lose streak gold (basically guaranteed if nobody else is using the "lose early" strategy)
It's possible that interest gold is also an advantage to doing well -- if you are ahead, you are in a more comfortable position to hold onto a lot of gold for bigger bonuses. You can do the same if you're "not trying" but the risk is obviously higher.
I argue first pick in shared drafts is too great of a reward for doing badly, and that it outweighs any benefit to doing well, at least for the first one or two drafts. Some item combinations are way stronger than others and getting first pick allows you faster access to these combinations which can easily put you at an advantage over the players at the alleged "top". This is bad game design. If you're going to give welfare to losers then the benefits should not outweigh the rewards for being good. You don't give better items to people who feed in League of Legends, so why would you do it in Teamfight Tactics?