Daf Yomi Nedarim 16b: Does The Mishna Give The Case Of Building The Succah?

From my Rif translation:

{Nedarim 16b}
Gemara:

רב כהנא מתני א"ר גידל אמר רב
ורב טביומי מתני א"ר גידל אמר שמואל
מנין שאין נשבעין לעבור על המצוה שנאמר לא יחל דברו
דברו אינו מיחל אבל מיחל הוא לחפצי שמים
מ"ש נדרים דכתיב איש כי ידור נדר לה' לא יחל דברו שבועה נמי הא כתיב או השבע שבועה לה'
אמר אביי הא דקאמר הנאת סוכה עלי הא דאמר שלא אהנה מן הסוכה
אמר ליה רבא וכי מצות ליהנות ניתנו
אלא אמר רבא הא דאמר ישיבת סוכה עלי הא דאמר שבועה שלא אשב בסוכה

Rav Kahana recited: Rav Gidel cited Rav:
And Rav Tivyomi recited: Rav Gidel cited Shmuel:
From where that we do not swear to transgress a commandment {that is, that the oath will not take hold}? For it is stated {Bemidbar 30:3}:

ג אִישׁ כִּי-יִדֹּר נֶדֶר לַה, אוֹ-הִשָּׁבַע שְׁבֻעָה לֶאְסֹר אִסָּר עַל-נַפְשׁוֹ--לֹא יַחֵל, דְּבָרוֹ: כְּכָל-הַיֹּצֵא מִפִּיו, יַעֲשֶׂה.

3 When a man voweth a vow unto the LORD, or sweareth an oath to bind his soul with a bond, he shall not break his word; he shall do according to all that proceedeth out of his mouth.

He may not break his word, but he must break a word in matters of Heaven.
Why are vows different, in that it states אִישׁ כִּי-יִדֹּר נֶדֶר לַה... לֹא יַחֵל, דְּבָרוֹ {stressing LaHashem, thus even for Divine matters}. By oaths as well, it is written או השבע שבועה לה' {--actually, it does not say this, but the word laHashem precedes it, as we see above}.

Abaye said: Here {by vows} is where he said "the benefit of a Succah upon me," whereas here {by an oath} is where he said "that I will not benefit from a Succah."
Rava said to him: But precepts were not given for benefit {/enjoyment, and so one cannot technically be said to be benefiting from a precept}!
Rather, Rava said: Here {by vows} is where he said "dwelling in a Succah upon me," whereas here is where he said "an oath that I will not dwell in a Succah."

Note that the case here is dwelling/living in a Succah. This is interesting, because this gemara is going on a Mishna that may or may not mention building a Succah as a mitzvah which interacts with neder and shevuah. In the Rif's girsa of the Mishna, this text about building the Succah is missing, while in the Mishna in our gemara it is present.

And here the case under discussion is Succah. Except of course that the issue is dwelling in/living in a Succah, rather than building it.

This may have connection with how to understand a Yerushalmi that talks about the blessing made for building a succah, and a blessing for building a succah for another person...

Related: The Rif Yomi video on the aforementioned gemara, runtime 4 minutes: