I am guessing that most of these belong to shooters? (R-type, or top down) Maybe an old NES platformer with no text? I personally cannot conceive a reason as to their existence.

I can personally say that I have never, nor could I imagine downloading something that was title screen only. Title, menus and credits in a very basic game (in the textual sense) possibly, but certainly not title only.

Edit: Nor have I ever heard of anyone downloading them.

In my case (all one or two of the ones that I've done) it's mostly a way to point at the game and say "Hey! This game's awesome!"

Heh, I don't have any reason for the latest one. Well other than I'm going to be reusing the graphic.

For hacks dealing with title screens (FF6->FF3US comes to mind), I don't have much issue with.

On the other hand, hacks that deal exclusively with this... I think there needs to be some additional requirement. Technically it doesn't serve much of a purpose.. it's only a title screen. For Japanese games, there is some worthy notion of translating the title, but then that's it... a title. It's not even a translation hack.. it is just a "small improvement patch". If the purpose served is to teach/help a new hacker how things work for a specific game's title screen, that would be appreciably better than "hey, the title's supposed to be called X". Title improvement patches ultimately don't serve much use except for those of the pedantic nature... so if it at least has some usable/understandable documentation, that would have some legitimate application/understanding that everyone can use.

As Gideon and King Mike have already stated, a title screen hack can call attention to a game of which people might otherwise never have heard. That's why I translated the Moai Kun title screen, it's an awesome puzzle platformer. By having the patch hosted on this site, it offers another outlet for people to learn about the game. (I believe I also changed the font to something more pleasant, so I suppose it could count as an enhancement patch as well.)

Hello Kitty's Flower Shop is basically a title screen translation as well, though there was one in game graphic that was also translated. I created that patch as part of my quest to make every 8-bit Hello Kitty game available entirely in English. (There's only one left and it's making progress.) It was also the first ROM hack done entirely on the toilet, so I think that alone justifies it's existence.

Now, the first entry you linked to sounds like there is more Japanese in the game than just the title screen, but the author couldn't locate it, so I suppose that patch could serve to entice someone to complete the translation.

As it's been said, it brings attention to an otherwise overlooked game. Many people wont even play a Japanese game because they don't know how much Japanese text is in it (even if there was none). With a translation patch of any kind the chances of someone playing that game greatly rises. With every patch there's also a sense of pride that we are getting closer to translating every Japanese game that commercial companies refused to do.

I thought I should expand on my comments, as I know many people have done them, and I forgot a whole genre. Shoot em up's seem to be very common in this regard, in instances where the games only need a title screen hack that is something I am all for. I thought we were referring to games that had only a title screen changed, not anything else.

When nothing other then a title screen is hacked, do we always place them in translations? Or is it a case by case basis?