Those DVD sound card+drive bundles weren't for connectivity to the drive in that era however (ATAPI and SCSI were the only standards for DVD-ROM drives). The bundle was to get a card with a hardware MPEG2 decoder since MPEG2 was taxing on the systems of the era.

With the exception of the TV out those cards were a terrible investment though. CPUs went from Pentium 120Mhz to Athlon 1000Mhz within 5 years and the playback software got optimized massively as well (CyberLink PowerDVD was a big success since it could enable MPEG2 playback on even a lowly Pentium MMX).

In fact i remember being given a couple of those cards in that era since pretty much everyone could play DVDs without the dedicated hardware and no one could be bothered setting up the drivers for it.

There was definitely a period in the early 2000s where having CD-RW plus separate DVD-ROM drive was a somewhat standard "premium" configuration— it obviously was great for duplication, or you could do stuff like load up multiple Encarta discs at once, or have both Diablo II discs in at the same time, whatever.

Back ages ago, I had one of the CD-ROMs with full audio controls and analog out, and used it along with a bare AT PSU and one of those drive-bay equalizers as a desktop CD player, no proper computer involved anywhere.