It is allowed on steemit, But There should be a limit, You can't vote yourself all the time, and take your self voting to 100 %, It still doesn't mean that you can't do 100 % self voting, yes you can do, but it is something that i believe everyone would like.
As you are newbie, there are other newbies too, who may comment on your post, you should support them with little bit of upvote,
It will increase your following. That will get you benefit in the coming future to built a community around you.
We all know that, we get more curation when we vote right after 15 minutes of post being post,
If you vote yourself after 15 minutes, it is always beneficial, you will get more curation reward, I have examined and it works also.
Personally, I don't feel that the return on investment is worth it for you to be renting Steem Power and upvoting your own posts. You might see some minor gains, but as you look at the over all value, it will probably not pan out for you.
The main reason rental services like that exist is because there is profit to be made by the person leasing out the SP. If the benefit or gain was not on their end, they would not be doing it. That is pretty straight forward.
I have a friend that was renting SP a while ago and eventually he decided to stop because he realized that the return was not equal to what he was spending. It was great for me because he was giving me a larger upvote than he had been in the past. For him though, it just wasn't that great of a deal. He would have been much better off taking that money he spent on renting the SP and instead turning into permanent SP for himself.
As for the part about using it to upvote yourself, I would do that at your own discretion. It is pretty rare that I upvote my own posts. Mostly because I forget, but also because I like spreading my SP out to other people.
If you were renting SP and only upvoting your own posts, I can see why people in general would have a problem with that. If you are at least upvoting some other people as well as yourself, they might be more forgiving about the whole thing.
It is usually only abusers that have their account looked at closely enough to catch anything weird that might be going on. I am sure there are plenty of people that lease SP and have no problem with it. I just don't see the value personally.
While you might be able to mathematically make profit renting SP and upvoting yourself, it is not something the community likes at all. If you upvote only yourself, you will catch some downvotes removing your rewards in no time. It is way more profitable to create quality content on steem, and get curators to see and upvote it. It does happen, and you can make money from that.
So please do not buy a delegation for the purpose of upvoting yourself. You will get flags for that. Instead, buy a delegation to get more significance on the blockchain, to get more known, and to be able to reward quality content. This way, you do way much better for the community.
Renting steem power is profitable when the price of steem is high but now, it's not that profitable because you may not be able to get your investment back let alone making a profit from it. If you have money to rent steem power, I would suggest that you invest such money steem now that the price of steem is low, hold and hope that steem's price rise in the nearest future.
To rent a steem power that would give you some meaningful profit regardless of steem's price would require you to spend some good amount of money. It would favour you more if you buy steem with such money than rent steem power.
Self-voting isn't a CRIME or wrong thing to do where no one is supporting your content. You are free to vote your contents by taking some SP on the lease.
I want to give one most wanted tip if you took SP on lease and you want to earn against that SP.
You can sell your votes after taking SP on a lease just like bots. You can use SmartSteem and Minnowbooster for selling out your votes to earn some coins for yourself.
Selling vote is well decision than voting your content because SELLING VOTES is more profitable. This way you get Liquid Coins and Curation Reward as well.
Apart from that, it's your wish how to use leased SP. Have a good day!