Not only are they being fined $500 a day during their absence, thirteen of them are being threatened with expulsion from their seats. I assume the rest are not because the House would lose its quorum. They need 100 of the 150 members to pass anything. Rs hold 88 seats in the House.
They are being threatened by the FBI and Trump. Then there's the aftermath. Their offices are likely to lose budget money and staff too.
But with their courageous stand, even if they cannot sustain it, they are helping build support for the redistricting efforts being taken by the Democratic governors. Absolutely worth the stand now.
It's hard (and costly) to be away from homes and families for an extended period of time. The financial costs are bound to be mounting up for them. Plus they are being subjected to unrelenting lies from the right, smearing their names, their motives. All of them have been threatened with legal and electoral consequences. And now the ones in Illinois have been subjected to at least two bomb threats.