"Sanji didn't use the RS as a form of power-up but rather he wants to save his friends by using it which he always does."
Sorry, mr leader-san, but I'm gonna disagree with you on this one.
The Raid Suit is quite clearly a power up.
In enhances his speed, it enhances his capability of taking less damage from attacks in general.
It gives him "true flight", instead of needing to constantly kick the air in order to maintain the Skywalk.
It gives him invisibility, which he can mix during a fight (World Trigger is a manga/anime where "invisibility" is used constantly by some characters there, and you can see the tactical advantages it can give in a fight. I recommend checking it out).
The boosters also enhance the power of his kicks (if Oda considers physics).
The cape works as a freaking shield.
It directly "boosts his stats" and add some new tricks to his arsenal.
The REAL problem with this whole thing is that there are some retarded kids that think the Raid Suit acts like this:
Instead of just this:
Liking it or not is totally subjective.
Saying that it "ruins the character" is not.
Base Sanji is, AT LEAST equal to Jinbei.
Raid Suit is the gimmick that, once again, sets him apart to be closer to Luffy and Zoro, than to the rest of the crew. That's it's "purpose".
"BU-BU-BUT HE SHOULD JUST USE HIS BODY".
I would agree with it, but since it's a dumb thing to consider, I choose not to.