It varies completely from person to person and what kind of streak you're doing. Nofap is mainly for people with masturbation addiction problems.
I have definitely gone on nofap then substituted with sluuts to get off. Personally I've realized this isn't what I want, so I nofap to channel my energy into pushing my life forward(currently single). I end up getting up extremely early with crazy boners, then working out, studying things that interest me, and am more dominant in pretty much every facet of my life.
To me, fuucking sluuts just to get off is the same as fapping. There's no real substance to the act, no real point, other than to release, which is lame and self defeating imo, so I consider that breaking a streak.
I force myself to only go for women I absolutely enjoy, and not just easy ones that I tolerate to get off. If I fuuck a woman I adore I don't count that as a reset because I can see a future with her, thus it isn't a waste of time, but again that's my personal take.
Being single and not fapping is the best inspiration I've found for staying in motion and breaking through barriers. To me fapping even once will make me more relaxed and complacent for that day or that hour, and that's one less day/hour I'm being relentless with my goal pursuits. My philosophy seems to be more extreme than most posters, but that's just who I am.
Fuucking in a relationship can still be considered fapping imo, if you're using the sex to validate yourself rather than to give to your partner out of abundance.