There’s a very good article titled Self-Spotting in the May/June 2023 issue of The Canadian Amateur magazine. The author Tom Haavisto VE3CX notes that in CW and digital mode contests their CQs are spotted automatically by skimmers. For phone contests, it’s a different matter.
Haavisto writes, “The difference is noticeable for phone contests. There is no phone skimmer so spots need to come from people who are manually generating spots.”
The ARRL allows self-spotting for all its contests. However, it’s important to check whether individual Provincial or State QSO Parties allow self-spotting for phone contests. The Arkansas QSO Party, for example, does allow self-spotting.