I think splicing can reduce the amount of thought you have to give to your liquidity. But ultimately as Burak describes it, inbound liquidity feels like a bug of the Lightning Network, and splicing IMO is just a work-around that's more efficient than opening channels on the fly but not a perfect solution.
I do think splicing can improve the UX significantly however and it could happen without you knowing. I wouldn't be surprised if LSPs offer incentives for agreeing to resize your channel as well, like maybe offering low (or even negative) fees if you shrink your channel if they want to reallocate the liquidity elsewhere.
Ideally we'd have some sort of "perfect" L2 where managing liquidity something you ever think about but I don't know what that would be. Maybe Lightning with eltoo channel factories or Hierarchical channels, or Ark.