Generally speaking, the purpose of discussions that we find in the Talmud is to understand the halakha that is derived from the Sages’ conversations, which lead to concrete conclusions that can be applied in the real world. The focus of our perek on applying capital punishment in cases where such punishment is appropriate according to Torah law appears to have no application in our day-and-age when the Sanhedrin does not operate.
This issue is raised by the Gemara itself on today’s daf. In the course of a discussion about how Rabbi Eliezer’s ruling about incestuous relationships is to be understood, Rav Naḥman quotes Rabba bar Avuh in the name of Rav that the halakha follows the interpretation offered by Ravin in the name of Rabbi Yosei the son of Rabbi Ḥanina.
Rav Yosef objects to this ruling with the exclamation hilkheta le-meshiḥa!? – are you ruling on a matter that will have no practical application until the days of the Messiah when the Sanhedrin will be reestablished? Abaye responds by pointing out that were we to follow that reasoning, we should not study the laws of the Temple sacrifices, since they have no current application. Rather we do this under the category of derosh ve-kabel sakhar – study it to receive reward – i.e. there is intrinsic value in the study of Torah, even if it is not currently applicable. Here, too, there is intrinsic value in the study of these laws.
Rav Ya’akov Emden suggests that the objection raised by Rav Yosef hints to the fact that even in Messianic times, the ordinary laws will remain in place, and that there will still be a need for the rules and regulations regarding the punishments of beit din (see Yeshayahu 65:20 “…for the youngest shall die a hundred years old, and the sinner being a hundred years old shall be accursed”).