I'm a bit upset about the fact we can't invest in
BTC.
If i wish to invest in this project, i'll have pay much fees in order to do it.

Maybe you can allow
BTC for the ICO ? Or creating some "fund" where people send
BTC, and you change them each 24/12/6h?
We might add BTC as a payment method after 2 weeks of ICO - just remember greater risk comes with greater reward, so contribution in CBX will get you the earlybird bonus (30%-17%), while a contribution in BTC will not.
Also, BTC contribution price per 4000 Sparks will be based on the CBX price
at that moment; it's possible that CBX's price could be much more expensive at that time, so you would lose this price increase too.
There are many reasons why we made this crowdfunding CBX based; for the investors in Spark as we are, a stronger CBX price will help start Quintessence on a strong footing.
the thing is CBX is traded on a small exchange with low liquidity.
Polo loves innovation and very picky, if you can deliver the new PoS chain with Smart contract, they will pay attention to spark for sure.