i always thought the entire point of BIAB was to save on equipment not time...
It can do both but you have to take advantage of the differences from a conventional mash tun which the OP did not.
With the conventional mash tun you are limited as to how fine you can mill your grains or risk a stuck sparge so most often the grain particles are left a little larger so that the husks don't get destroyed because those husks are important in creating a filter when it is time to drain the tun. With those larger particles you need a longer mash to get conversion because it takes more time to wet them through and activate the enzymes.
With BIAB you aren't limited by the milling so you can mill the grains really fine. That will tear up the grain husks but you don't care because the bag forms the filter, not the grain husks. With those fine particles of griain, they wet through very quickly and conversion is over quite soon. Because you have conversion done you can cut the mash short. I suggest you don't go shorter than 30 minutes but I have made beer with a 20 minute mash and had full conversion. That just saved half an hour on the brew day.
Most of the modern malts don't have a significant amount of SMM so it doesn't convert great amounts to DMS that has to be boiled off so you can cut the boil time from 60 minutes to 30 minutes if you adjust the amount of hops for bittering. That cut another 30 minutes off the brew day.
People have claimed that cleaning the bag out when the mash is done is taking significant time but I dump that while the wort is coming to a boil, rinse it out, an hang it to dry. Half my cleanup is done while waiting for the wort to boil which also cuts the time.
I'm usually only doing a half size batch due to limitations of fitting the larger kettle on my stove and doing it all in my kitchen. Waiting for the water to heat up or the wort to boil is a large part of the brew day but if I had a big propane burner and brewed outside that time could be cut a bit or a larger batch made in the same amount of time. By being well organized I can bring equipment from the basement, weigh and mill the grains, do the mash, do the boil, cleanup and put equipment away while the wort cools and have everything done with the yeast pitched in about 3 1/2 hours. YMMV