>>52659564
>Use any magical items
How often do DMs give you magical items you can't use?
And even then, it's a later level feature at which point AT is laughing because they can haste themself and sneak attack twice a round using readied actions.
>Pocket sanding people
Maybe works at level 3, but beyond that it's unlikely to be awfully effective.
>Adv on stealth checks
Actually a pretty decent feature, but honestly usually the problem is your teammates rolling low on stealth, not you, and pass without trace exists. At-will charm person is better, really.
>Spellcasting
Yes, AT is great, but it feels stupid to grab booming blade with high elf then go AT. .. But maybe that's just me, it works fine.
>Assassin's assassinate
Comes up a lot less often than you'd think, and their later level features suck. Anyone can try to make false identities already, really, even if it's not as effective. Not that people check your identity so thoroughly very often. It's really just a 'You might rarely get some extra crits or otherwise just get some advantage' which is hardly interesting and in which case you might as well be a ranged rogue, especially considering you can snipe from sneaky spots.
I'm not saying swashbucklers are the best at all, but for someone who has booming blade it's a pretty easy to run with and logical pick. If you want to be the best at everything, you just go AT.