Those things are a god send - not sure if you can get them on the other side of the Atlantic (but there is no doubt an EU/UK equivalent) but they take the time and general ballache out of bleeding brakes. I was installing the summer tyres on my wife's GLC and said while I was at it, I would do a B Service which includes a brake fluid flush and it was done in no time.
That they are,I also use my hand vacuum pump to draw out air in some cases,the power bleeder is really good for a proper removal of old fluid ,the one I bought was expensive but worth it as I hate brake work with a passion so the sooner over the better . IMO you can use a one man bleeder or speedbleeders but you risk pumping all the shit fluid and damaging cups and seals ,using a vacuum system you can reduce this issue by a lot.