E.g. Tartarus instead of Tartaros, Daedalus instead of Daidalos, Cerberus instead of Kerberos, Cassandra instead of Kassandra… There are a lot of these names that are more widely used in their Romanized forms. Yet if we talk about mythological names instead the Greek names are more widely used (althrough this was different over 200 years ago)
The classical Romanization was more accurate in its time—the issue is that the common pronunciation of classical Latin changed after the classical era (for instance, the “c” became soft in many contexts, instead of always being pronounced as “k” as it was in classical Latin).
If you use the original classical pronunciation for Latin, you’ll also pronounce the classical romanized Greek names correctly—and if you spell them the classical way you’ll recognize them more easily in Latin sources. The modernized romanization is most useful if you’re only interested in Greece and not in the classical world as an integrated whole.