Elo boosting has long been a rejected act in League of Legends, imagine playing a game with a boosted account in high elo and everybody on your team is synergized with all the macro reading your team is making, while one player keeps on dying because their skill level is stuck in a much lower Elo.
Instead of having a full synergized team, you will have one teammate who feeds the opposing team and will lead to snowballing enemy champions that can be really hard to deal with. It will feel like it is a 6 vs 4 game.
Elo boosting is never worth the money in League of Legends, imagine paying tons of money to a good player and having your account be boosted from silver to diamond. The player only needed a few days to boost your account and once you play your account in Diamond, you get surprised because you are being destroyed by players in that rank as a result you receive lose streaks upon lose streaks and wonder why all of your teammates are flaming you.
Eventually, you get de-ranked until you reach your original rank. This is what makes Elo boosting not worth your money. You get sent on a rank that you cannot even play and eventually get de-ranked, all the money you used for boosting turned out to be useless and it will feel like you just threw your money away.
Elo boosting should never be okay with the community, there is even an infamous player banned for a very long time in League of Legends because of excessive Elo boosting. He was the rival of Faker when it comes to solo queue and Mechanical skills and he is called DOPA.