If using the same login name is bad security, then I'm really setting myself up for attack, and I have a lot of work to do to correct that, including an intensive google search because I've been through a LOT of places in the past years...
Using the same login name isn't really a security risk. The user name I use ssh'ing to my Linode happens to be my real life name, and I can't be the only guy who spells it "kris"

Sure, Piki may be a pretty unique name (which is why I chose it), but that doesn't prevent others from using it, so there's no guarantee that a Piki on another site is the same Piki as me, that Piki could be a girl!

It's much more important to have a secure password and to have that password encrypted using a strong encryption method before sending it across a network. I've taken that two steps further and have required RSA keys via ssh and I changed the port, in addition to using strict iptables (which should be done regardless).
The only really reason I want to have the user alias setup is purely a matter of habit -- Piki has been my default handle for a couple years now, so it's automatic that I type Piki whenever I go to login anywhere, and it's annoying that I keep getting kicked out because I don't have a Piki on my server. Of course, I could just create a new user, but I'd still keep my old user for emails, and I have no other use for two users for myself other than making ssh easier, so that'd be useless for me.