It's slow to connect, uses a lot of resources and cannot be installed without bringing in hundreds of megabytes of dependencies (e.g. X11, Gnome libs).

> It's slow to connect

It connects to my home wifi in <1s. How long for you?

> uses a lot of resources

10 MiB and 9 minutes of CPU time after an uptime of 4 days with many reconnects, which is totally reasonable.

> cannot be installed without bringing in hundreds of megabytes of dependencies

Not true. Even on Ubuntu, it only pulls in 17.4 MB of dependencies:

   apt-get install --no-install-recommends network-manager

   The following additional packages will be installed:
     dconf-gsettings-backend dconf-service glib-networking glib-networking-common glib-networking-services gsettings-desktop-schemas libbluetooth3 libdconf1
     libgudev-1.0-0 libmm-glib0 libndp0 libnl-3-200 libnl-genl-3-200 libnm0 libproxy1v5 libsoup2.4-1 wpasupplicant
   [...]
   After this operation, 17.4 MB of additional disk space will be used.
   Do you want to continue? [Y/n] 

On RPM based distros, it's even less. They made it the default network manager on RHEL 7, even for the minimal cloud images.

Try installing it on Ubuntu headless server, then it will bring in hundreds of megabytes. You obviously already had most of the dependencies installed. Intel developed Connman because NetworkManagers shortcomings make it unsuitable for embedded devices.

That was on a headless server, 16.04 cloud image.

It pulls in much more without --no-install-recommends, but you don't need any of those.