Is this a garbage opening, or what? (1.c4, b5??!)

Hard to believe someone played this (in a serious game, no less - not chessdotcom blitz). Anyone here ever seen it before?

I find it even harder to believe that they guy playing black is 2/3 of the way toward attaining a title: I was told he has 2 norms under his belt. (However, a check of his results on official ratings pages of USCF and FIDE finds no norm-worthy performances. In one event he did have a performance close to 2450 -- the IM norm threshold -- but he played only 7 rounds, and 9 is needed to be eligible for a norm.)

Technically it's bad. But proving that almost always leads to wild complications where someone can hope to outplay their opponent. No one is just going to sit there and let the passed pawns roll them over.

This openings has its name English opening: Jaenisch gambit. There are 13 games in the Explorer. Tilmann Vogler played it thrice with the impressive score: 2 wins and 1 draw.

https://www.chess.com/games/view/709712

https://www.chess.com/games/view/877428

https://www.chess.com/games/view/1056741

Btw ChessOK / Houdini evaluates it at only +0.37 which is quite reasonable for a black's gambit.

over 100 games with it in my database with black scoring 48% 

It's not garbage but it's a risky choice if you're playing a strong opponent. Black will attack with the 2 open files on the queenside. I play to avoid exchanges if possible for a while to create counterplay. I've played the Jaenisch a handful of times in tournaments.

Looks like a (much) inferior version of the Wing Gambit, since the colors are reversed. 

 Interesting mentioning the Wing Gambit... I hadn't thought of that, only the Benko (without a White d4 or a Black ...c5, as someone mentioned earlier). Yes the way Vogler treated it is indeed like a Sicilian Wing Gambit with colors reversed. In contrast, my opponent (whose rating is about the same as Vogler's) avoided an early ...e5 and fianchettoed his KB, as in the Benko, then went on to play ...c6-c5 and ...e5 (after I recaptured on d4 with a piece). 

Incidentally, the games shown in the links were played in real tournaments, not here on chessdotcom. ChessBase Big Database 2017 contains the 3 Vogler games plus 2 others, both draws (I filtered out all games where either player was below 2300). So, an overall record of 70% for Black. However, there is no GM or even IM practice with this gambit: the highest rating in any of those games was only 2402.

The advantage of the Wing's Gambit is that at least white gets control of the center better, without the c5 pawn.

With this terrible opening, there isn't even that, since white can occupy the center easily, having an extra move, making a big difference. 

only insane d4 players would play this since if you play 1. d5 immediately, you are trading a flank pawn (C or F pawn) for a cente pawn which is bad

like 1. c4 b5 2. cxb5 d5

Jaenisch Gambit.

A rare line for English players to know.

I used to play this then shifted over to 1.c4 e6 recently

It does look sub-optimal and also that he played the middlegame kind of lamely. I thought he would try to go toward the Benko Gambit and play Ba6 instead of the Na6 but maybe I'm not all that up on whatever this is.