c3 - Saragossa opening. Is it good?
Back to the original question.
1.c3 is actually a very decent move practically speaking. The aim of an opening is generally to achieve a position you are more comfortable playing than your opponent and 1.c3 gives a good chance to confuse your opponent into playing unfamiliar positions, at very little risk as c3 is solid and useful.
1.c3 e5. Presumably played by e4 players or just on general principles. However after 2.d4 exd 3.cxd4 we reach a queens gambit declined exchnge variation. If black does not know the theory (very likely wont) then he can easily get into trouble.
1.c3 d5 white has many decent tries. 2.f4 goes for a reversed dutch, where white can either head for a stonewall or leningrad structure. 2.d4 instead can lead to a london system if white chooses, and the move order cuts out the lines where black pressures b2 or white can just play reversed slav. The Colle system is another option. Again if black does not know it he can quickly b worse. Or be more original with 2.d3 or suchlike for reversed old indian type stuff
1.c3 c5 white can play 2.e4 for a c3 sicilian or if happy to draw play 2.d4 for very solid but boring, or play 2.b4 which gives more original positions
1.c3 Nf6. Again white can play d4 and choose any number of setups. Torre attack one possible or just develop colle style and eventually play e4. Another option I like is to play 2.Qc2 3.d3 4.e4 and go into positions that are similar to philidor/old indian reversed type positions
Basically white does not need to learn a huge amount of theory gets good easy play, decent positions and a middlegame he likes, while black if he is not careful gets tricked into plying something he does not know.

FYI:
The opening is named after Sara Gossa (1814-1891), was suffered from triple vision.
I have it on good authority that it was named after Sir A. Gossen, who had very short arms and couldn't move his Pawns past the third rank.

the problem with 1.e3, 1.d3 and 1.c3 is that they have almost no independence significance, and their transpositional value is harmless. (compare this with move like 1.nc3 and 1.g3 which can be played without necessarily transposing and get interesting play).
Trying to play these moves as their corresponding black defenses a tempo up is not particularly advantageous at all (1.d3 is prob the best of the 3 in the sense, if you play it like reversed pirc, but 1.g3 is probably better for that purpose anyways)
i really think of the 3, 1.c3 is just the most harmless. I have never seen an objectively respectable line that is really not a meek version of something else with it. You can 1. play a sort of caro or slav like formation a tempo up which you would be lucky to maintain an ounce of advantage 2. tranpose to a sicilian or old benoni with a sly tempo delay 3. try to force your way back into pirc-like territory hoping c3 didnt restrict your options too early. It just fails to meet the criteria of the two main philosophies of white openings; it neither fights for advantage nor try to steer the game into juicy complexities.
That's why you never hear of the e3,d3 ,c3 trio. They are objectively better than their rarity in otb play at high levels, but thats it.
If I was going to play 1. c3 I would probably play it as some sort of colors-reversed Pirc or King's Indian... so I wouldn't be playing 2. d4. Not unless I was heading for a reversed Caro-Kann.