So far the "network effects" have been coincidental: one small group of colleagues registered on matrix.org after one more colleague from our small circle turned out to have a home server. There are 7-ish of us now, 2 with their home servers (myself and the "other colleague"), and 5 with accounts on matrix.org.
To go "native", I see one lacking point with discoverability: I don't know of a way to discover my "contacts" whether they use Matrix without asking them first. Which is not true in any other messaging apps I have tried: Signal and WhatsApp use my address book and their phone numbers, Messenger is tied to my "friends". However, although Matrix allows entering phone and e-mail identifiers, I haven't seen an easy way to "find" them. Any pointers?
Overall, Synapse is easy to install and run. Took about two evenings to configure synapse + 3 bridges (whatsapp, messenger, hangouts).