The word "invest" implies an expected return. In the context of DAM, the "investment" is in a DAM token which "returns" FLUX tokens. Sounds cool. However, the only purpose of FLUX tokens is to be burned. So the real measurement of return will be return on capital (in the form of ETH, likely, or maybe USD). Let's do a thought experiment.
Let's say you've got 1,000,000 DAM and are earning .01 FLUX every 15 seconds. Then you have all the multipliers except the 10x burn so now you're at .03 FLUX every 15 seconds.
But you're soooo close to that 10x multiplier, so you buy some FLUX to burn it. Great - what's your reward? You get back MORE flux than you burned.
You bought the FLUX to burn with ETH. For ease of explanation, let's say you paid .05 ETH for 1 FLUX to put you over the 9x burned / wallet balance ratio. Burning this 1 flux nets you an extra .27 FLUX every 15 seconds, so soon you've got 5 extra flux to sell to recover your .05 ETH. But you're profit seeking, and probably want to at least double your returns. This is Crypto, after all, and you're interested in a 200% return for about 10 minutes of work. So you sell your 5 FLUX at .03 ETH each for a total of .15 ETH, recovering the initial buy in plus a tidy 200% gain.
The guy who bought one your 1 FLUX at .03 each for .03 ETH similarly has 1,000,000 DAM and are minting .03 every 15 seconds. Soon he's got 5 FLUX to sell to recover his .03 ETH. He's also profit motivated, but not unreasonable, and similarly wants a 200% return for a few minutes of work. So he prices his 5 FLUX at .018 ETH/each and they sell. He makes a 200% return and the cycle continues.
This is the inherent deflationary mechanism in the burn to print model. No rational investor, who is seeking return on capital, is going to buy FLUX to burn it expecting a loss. The only people burning FLUX are doing so because they expect a return. The return won't be in FLUX, but in the base currency (ETH) in this case.