But isn't the liquidity issue same to SPECTRE? Where does it mainly differ? Simple and short explanation, please.

From the one pager document here: http://spectre.ai/media/spectre_one_pager.pdf?ver=1.9

HOW WE DO IT

SPECTRE (short for Speculative Tokenized Trading
Exchange) is the worlds first brokerless, financial trading
platform with an embedded, decentralized liquidity pool
that acts as a counter-party to all trades. The liquidity
pool is initially funded by an ICO and tokens are
distributed to the investors in return.
When trading, all transactions are governed by smart
contracts meaning that the broker is completely removed
from this equation as well.
The smart contracts pay out 2% dividends to ICO token
holders and 2% to SPECTRE as a technology fee, each
time the trader takes a trade. This is different to the
traditional broker models where brokers mostly get paid
on trader losses.
A result of all the above is the creation of a fully
transparent and fair trading environment with no conflict
of interest between involved parties; a provable fair
battleground where traders can fairly trade against the
market without intervention.