please note that in Bitcoin, connections with peers, either inbound or outbound, are full duplex, i.e. it is not strictly needed to have inbound connections for participating in the network though it yields a much better topology, having more nodes advertised as being ready for incoming connection requests.
A lot of people disable on the GUI the option of "allow incoming connections" because they are paranoid that this means people are able to connect to your node, gaining personal information, perhaps even performing RPC. I have seen this numerous times:
https://bitcoin.stackexchange.com/questions/98555/what-exactly-does-the-scary-option-allow-incoming-connections-do-in-bitcoin-coI think it should be clearly explained what it does otherwise we lose potential connectivity from all these people being scared to keep that option checked.
Explanation isn't very useful when most users don't bother read documentation or perform research. One possible idea to do it is by adding more information user highlight "Allow incoming connections", but no one will read it if the message is too long.