But it has gold caps and everything!
Conventional electrolytics with a gold-colored jacket, anyway. A literal
Gold-Cap[tm] would be a double-layer / supercapacitor.
Generally I don't even mind the idea of running 3D TLC NAND in pSLC mode, so basically as all SLC cache... it certainly wouldn't be hurting the speed or write endurance. This approach seems to be semi-common in the industrial / embedded world. You can order a Swissbit X-76m2 series M.2 SSD with 320 GB (using 1 TB of TLC NAND) for about 490€ a pop (or ~400 in 5+ quantities), for example... while a plain ol' SATA interface job only, minimum endurance is given as between 2070 TBW (enterprise workload) to 10520 TBW (sequential workload). For comparison, it would take a 2 TB Samsung 860 Pro or a 4 TB 870 EVO to be spec'd at 2400 TBW, neither of which you can even get in M.2 formfactor (2.5" only) and both of which cost somewhere around 400€ as well.
This SSD apparently
sells or at least used to sell for 800 USD while sporting 8-layer mil-spec PCB and other fancy parts goodness (and it's actually PCIe), so at least it's not
outrageously overpriced compared to other similar options. It's still a boutique product with little in terms of proven track record, of course.
Now do you actually need such a beast for audio playback? Hell no. Audio files tend to get written to very infrequently and a larger collection is likely to outgrow a 320 / 333 GB SSD, so like most ordinary users, you should be favoring a different size / endurance tradeoff. Just get a nice 1 TB or so M.2 from one of the big guns like Samsung or Crucial or whatever. The plain Samsung SSD 980 has the same spec'd write endurance as the 980 Pro, has a less fast interface which has little practical relevance and only costs half as much. Crucial P5 is similar and also comes in a 2 TB version (1200 TBW), which can be had for ~200€ right now. As a bit of a wildcard option, there's the Transcend MTE220S 1 TB M.2 PCIe 3.0 drive which claims 2200 TBW (~130€) and twice that at 2 TB (~235€), or its PCIe 4.0 cousin MTE240S 1 TB at 1700 TBW (~160€). (I would not take bets on the comparability of endurance specs between manufacturers.)
If 2.5" is fine (unless you are literally copying large files between drives, you'd basically never notice the difference between NVMe and SATA in everyday life), there is little wrong with a 1 TB 860 Pro or 2 TB 870 EVO or Crucial MX500 either. (WD Blue / Sandisk Ultra 3D seem to have a bit of penchant for the controllers dying at 1 TB size and up, which may be down to insufficient heatsinking in the plastic case. I like using the 250 GB version in office machines, as the smaller size MX500s get progressively slower.)
I would not stoop so low as to be considering bargain basement drives like the BX500 (cacheless + QLC, ugh), and even the 870 QVO is more geared towards capacity than one really needs for music (you want at least the 2 TB version of this model for somewhat non-pathetic write speeds outside the SLC cache).