Yes, the speedbleeders are put in place of the bleeder fittings at the calipers. This is not a pump, vessel and gauge system. I have the Master Bleeder and it works okay, but you don't have a lot of pressure.
The speedbleeder fittings have a check valve. You put them on the caliper and when you loosen them the check valve allows fluid out when you step on the brake, but does not allow air back in when you release the brake.
After bleeding a wheel, you simply tighten the fitting and that wheel is bled. You are using good pressure to really blow the air and fluid out with a vengeance. The 20 or 30 PSI of the master bleeder works pretty good for flushing, but I have never used it for bleeding a system that has been seriously opened up for caliper repair or replacement.
Have a great day,