Personally, I'm firmly on the pro-immigration side of things. But leaving that aside and trying to be an impartial referee with these bus stunts?
The GOP gains some ground for both trollishness and making their case even if they lose some for the flip side of that--lack of seriousness as a policy rather than a point. Democrats lose some for hypocrisy, given that many of their responses place NIMBYism above sanctuary, and the two are incompatible.
The GOP border leadership can make the following case to voters: “Hey, we think excessive illegal immigration is causing x, y, and z problems for our states and we don't want these numbers because of the strain we think it's causing here. Sanctuary cities deny or downplay those problems, and claim all immigration is wonderful regardless of it's legal status and are offering a place in their cities for migrants who just want a better life for them and their families. This seems like a win-win, as we both get what we want where we want it.”
Dems can point out correctly that this is all a cynical political stunt, that a couple of busloads here and there is nothing compared to the sheer numbers of migrants crossing the border every day, and that the intentional lack of coordination is making resettlement harder than it needs to be. All of this might be true, but the overall case the GOP already made still remains and has already sunk in where it's designed to. And instead, many on the Dem side have fallen into the trap by saying with words or action that even these small busloads are difficult to deal with, unintentionally making the GOP's case for them.
As a policy, busing fails under the logic of it's own supporters. They often make the claim that sanctuary cities encourage greater amounts of illegal immigration because of the protection it claims to provide them from federal law. Well... if you're looking across the Rio Grande eyeing up Brownsville or McAllen, or if you're washing up on the shores of south Florida... it's gonna be much harder to reach somewhere like Chicago from there. A free bus ride (comprised entirely of immigrants who claim to want to go to these places voluntarily), would only sweeten the prospect of taking that risk.
It's not about whether or not it's good policy for these policy makers, though. It's a high visibility news story of their creation that at most charitable is meant to advance their narrative to affect more broadly their preferred policy preferences, and most cynically (and correctly) meant to advance their standing in a future Republican primary contest.