Likely something that will let them capitalize on e-sport bucks. Two other games I play a lot tried this and failed miserably, and I find that really painful.
The e-sport scene has to form naturally, you can’t just force it.

The arena seems to have some merit, at least with a 1v1 in an arena there’s no off-grid repping (if that’s still a thing).
Off-grid repping? You mean neutral repping, or off-grid boosting? Those haven’t been a thing for some time now.

Much easier to see what went wrong when it’s one v’s one rather than lost in a blob v’s blob fight. Has some real possibilities for training where nobody else can interfere.
In EVE you throw them into a war then give them the gun. Better to learn to use the gun first.
I teach new players how to fight, and I have to say that I disagree with this sentiment to a large extent. Throwing players into the fire (but being there to act as support, and to provide the necessary information before and after) usually leads to better results than extensive amounts of staged practice.
And blob versus blob isn’t really a “fight” anyway. It’s just a series of interactions with a largely textual interface, with tactics and movement being centralized and out of your control. A blob fight to a small engagement is the same as what ordering fast food is to cooking a home-made meal - you’re going to eat something, but the quality and satisfaction will be vastly different.
Can arenas help train someone for PvP? Possibly, to some extent they can. But EVE PvP is much more than just positioning yourself and activating your modules - timers, psychological games, the fog of war, et cetera, all play major roles in it.
Also, I’m going to venture a guess that the grand majority of players doing arenas aren’t doing them to “practice PvP,” and those who do want to practice PvP are unlikely to try to do it in arenas, or at the very least won’t try to do so for a long time, because they’ll keep getting annihilated without recourse by the top-end PvPers grinding the leader boards. Maybe when proper matchmaking comes out? Even then, hard to say. Historically, in games I’ve played, arena-like features weren’t seen as the initial steps toward learning PvP, but as the end goal.