I do not doubt that it was worth it to have the clean grout but I think I'd at least try the steam cleaner first. Just personal preference and BTD is becoming a sacrament in some circles here. Who woulda thunk it? From recycling dryer sheets to BTD in one generation of FIRE! YMMV
I do have a steam cleaner that I used for several years on the grout. The steam cleaner worked great cleaning the grout at the beginning but became less effective as the years passed. The grout in the tile floor was from 1999 and I had sealed the grout at least twice. 18 years after tile & grout installation, the Grout Pro cleaning, sealing and painting made the grout look new and was worth the money.