If I recall (its been 25+ years and my copy is in storage), they went there to wait for other civilisations to develop. They were truly early life and there was literally nobody else and they determined that they would be waiting for millions of years, if not billions.

I don't know if it was this book, but the 'suspended animation' was basically pushing several large stars and neutron stars close enough together that the flat space between them was inside an encompassing event horizon, and there they waited, living their lives at an extremely slow (compared to the outside universe) pace.