I don't think Apple ever provided 6 thunderbolt ports on anything, though. This (and the other product with just the Thunderbolt hub function) do that. It's probably only possible now due to Thunderbolt 3, but still. That part of it is useful for any Mac no matter how many ports apple provides - because many Thunderbolt 3 devices 1) do not have a daisy chain port and 2) do not use the full 40 Gbps, leaving available bandwidth unused...Dongles, hubs, and the likes would be a thing of the past if apple just puts the ports back into their Macs. Plenty of space given how small the M1 based logic boards so it shouldn't be a brainer.....but maybe apple doesn't want to lose on that cash train on accessory sales huh?
And as was said, it adds "dock" functionality to laptops so you don't have to plug and unplug multiple devices when moving from place to place. One cable with everything including power.