What are the advantages to configuring and using an MTA?
 

I was wondering what the advantages are to configuring an MTA? I run openSuSE 12.1 and use wireless LANs in libraries and coffee houses, so I am not connected to the internet all the time. I am looking to eventually set up a LAN in my apartment, where I would set up a Linux box as a firewall. Would a MTA be useful?

I don't think I have an MTA installed at the moment. nstat -tanp|grep 25 gives me no output

If you don't know why you'd need an MTA and have to ask, then the answer is "you don't need an MTA". I'm not meaning to sound flippant, but this answer is the truth. For a typical single-user home computer (or just a few family users), then you'll do just fine using one of the bazillion GUI-based standard email clients. When you get into large multi-user systems or systems where you want to send/retrieve email from programs you've written (that don't interface directly with people), then you will find an MTA useful.

Support for openSUSE 12.1 ran out on May 15 2013. It would be better to run something supported, if possible (see here). If there is some valid reason that it really has to be an older version of openSUSE (and, usually, there isn't), look into the link for 'evergreen' versions on that page. Or, find something supported for a longer period (eg, Centos).

One advantage an MTA has is unattended operation.

If your recipient mail server is off line (or you are), an MTA can hold your sent mail messages and retry at later times.

The usual (configuration defined) maximum hold time is 5 days.

The NORMAL use of an MTA is to act as a mail server for one or more users - receiving mail at various times and delivering it to local storage for reading.