That looks like many 57s I have seen. Those long stress cracks dont usually compromise the bows performance. I actually backed one with snakeskin that was in better shape than that one. The little pits and splinters and flaky glass drive me nuts.
With the bow flexed on a tillering board I applied super glue to anything it would run into.
I'm sure the bow I had was safe to shoot but I figured with the super glue and titebond II for skins and the skins themselves the bow would be a solid shooter for decades.
At the very least I'd want to treat those stress cracks with locktite and then seal out any moisture with a good finish.
Trap