I believe operating as a "state-chain facilitator" to make some profit in fees will pay more than operating a Lighting node because the UTXOs/liquidity in the system is pooled within hubs which users can transfer freely with other users who probably are connected to the same pool or to another high liquidity pool?
It would not be that easy as setting up a Lightning node, because the problem of Statechains (and the reason why I'm not really interested in that concept) is that the operator is an entity which can steal coins with no possibility for the user to penalize him and claim his coins back. This needs some conditions to be fulfilled, basically the Statechain operator has to be able to become an user of one of his own Statechains to steal the funds, but in an anonymous/pseudonymous setting this probably isn't that difficult.
Thus as a statechain operator you must gain trust in a much more pronounced way than as a Lighting node operator. As far as I interpreted the article from Bitcoin Magazine linked above, mercury channels don't change that, because the private key shared between statechain operator and user does not change, it only is "reconfigured" when the user transfers the "statechain coins". Mercury channels "blinding" can however make it more difficult for the Statechain operator to "chase" the users of his own statechain to eventually receive the coins themselves, as they have less knowledge about their activity.
But the primary attack I see is: The statechain operator opens a statechain with itself and then tries to exchange these coins to another user, and once the other user has fullfilled his part of the exchange (e.g. delivered an altcoin, a good/service, fiat etc.) he steals the coins as he has always access to the whole private key.
The "statechain operators" thus - as acknowledged by the creator of the original whitepaper - will be thus mostly federations, like in Liquid, and thus for individuals without recognition and trust in the crypto space it will be very difficult to become part of one of these operators.