no, people don't usually buy swords to slaughter chickens, nor do they use swords as kitchen knives. people usually use swords for self-defense or offense, neither of which was the case here. it was a case of a fulfillment of a particular prophecy. and it is not a fulfillment of a prophecy of 'buying swords', the prophecy in question is that he will be 'numbered among the transgressors'. and 'being numbered among the transgressors' doesn't necessarily mean he actually is a transgressor (or that he will have to be one). in context, it actually means 'although he is not a transgressor, he will be numbered among the transgressors'. and happening to have two swords in procession is sufficient for this particular prophecy to be fulfilled without the need to actually make use of any of these swords. this is corroborated by - what you are actually conveniently and deliberately ignoring - the very passage you quoted the verse from, the entire NT, and those who wrote, transmitted and applied the NT and grew in numbers while doing so for at least the first three centuries (Christianity is fully and naturally itself by not -militarily- resisting and confronting the enemy). what better way is there to end this than by adding the ending quote of the very passage you 'quote-mined'? (after healing the guard's ear that Peter had disobediently cut off with the sword), Luke 22:52 Then Jesus said to the chief priests, the officers of the temple guard, and the elders, who had come for him, “Am I leading a rebellion, that you have come with swords and clubs? 53 Every day I was with you in the temple courts, and you did not lay a hand on me. But this is your hour — when darkness reigns.”
the argument really boils down to this: is the narrative - Jesus wanted at any point to militarily confront those who were opposing him - supported by the relevant data at hand? or is it that in the process of making and holding on to that narrative one will have to unwarrantedly ignore parts of the relevant data (read: all of it in your case)?
now, in my defense of apparently making a rather irrelevant minor mistake; the mention of 'roman soldiers being among the armed Jewish crowd that came to arrest Jesus' does indeed occur in John, but is omitted in the other three gospels, probably due to those soldiers' presence being of a relatively low nature in that scene (still a far cry from the way you were trying to portray it). however, the thing is that whether or not there were roman soldiers, it is absolutely of no relevance in terms of validating the bizarre narrative you're forwarding. you will have to support the claim which you're basing the narrative on, namely, that Jesus wanted to make a military confrontation - at all - or - at any point - to begin with (whether against the Romans or the Jews, is of no relevance at this point. hence my seeing no need to double check for the existence of roman soldiers at the scene). to reduce your reply to the question of whether or not roman soldiers were present at the scene is to simply evade the charge and clutch at straws