Is this RARE idea good? (Opening; Four Knights Game)

1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.Rb1

According to ChessGames, the FIRST time it ever got played over-the-board was in 2017;
It seems, GMs Savchenko and Moiseenko *both* have played it thrice OTB;
According to Stockfish eval, it doesn't make the position THAT much worse than the mainstream Gunsberg Variation (i.e., 4.a3).

So... does this idea deserve more popularity?

@Neverness said in #1:
> According to Stockfish eval, it doesn't make the position THAT much worse than the mainstream Gunsberg Variation

Now there's a ringing endorsement!

It may be rare from OTB point of view but not at all rare with respect to online chess.

In the 4-Knights virtually every legal move has been tried. 4. a3 was a pet line of mine

Oh yeah, I just saw somebody else play 4 a3.