Currently a 30 day MCT is 1.6b isk in game. On my account management page I can buy 30 days MCT at £15.99 or I can buy 500 plex for £16.99 from CCP which I can sell (at the current plex price) for a tad over 1.6b giving me 1 months character training for £15.99 or £16.99 respectively.
Or I can have multiple accounts with one character on them for £9.99 a month (or less if i buy multiple months at a time) essentially allowing MCT for £9.99. So what is the advantage of using all your character slots per account when you…
A: Can train multiple accounts for less than buying an MCT by having 1 character per account over multiple accounts.
B: Can log on all of those accounts at once (as long as they are Omega of course) whereas with characters on the same account you cannot do that.
I know that there is currently an offer on MCT if you buy 3 months Omega, I am talking generally when that offer is not available.