buying more tickets will only give you higher chance of winning but still there is no guarantee, no one can even say that freebitco.in's lottery is provably fair. personally i see that feature as just another thing to catch bitcoin users attention but no one really wins on that unless someone provide here proof that he got the prize from there

   Lottery is gambling, and chances to win there are less then 1 %. Did I said 1 %, better to say 0.0000001 if you are playing some high paying lottery with lot of participants. Lotteries on National level with first prize in millions. Chances with one ticket are very, very low.
   I don't like lottery, and I never played lottery. For me there is other games where I can use my skills to win something, lottery is just waiting.
   I heard about people who buy more then one ticket for lottery, and every ticket with some new combination. And in the end guy who bought one ticket win. This game is not for me, I like to control thing around me as much as possible.

Yup, it's totally gambling and can be as addictive as any other form of gambling.   I'm sure you've seen these poor saps in the gas stations scratching off their lottery tickets.   Well it's even worse online and you can lose all your bitcoin a lot quicker.  Have fun but be very careful.

Lottery is also gambling because your buying tickets which gives you a chance to win the pot. It could be addicting to other users and for your last question yes we could say lottery is a second form of gambling. Adding this quote I got from a site about your question.

of course it is gambling, remember that you are betting something for profit, so it means that you are gambling.

The more lottery tickets doesn't give you guarantee for sure, it can only increase your winning chance there because lottery result is depend on our luck, where outcome based on luck that is pure form of gambling, lottery can be a little bit different but it is very similar gambling.

I think there are two definitions, can be regarded as gambling or not. and your case here only buy a ticket to expect prizes by lottery. I think this is not gambling.

Playing a lottery is like playing dice with extremely low odds of winning but high pay out.

I think it is less addicting though than real life lotteries. In real life, people often buy tickets every week because they don't want to risk not winning when their neighbour wins for instance (we have a postal code lottery, that one is really sucking people in for this reason).

Does it really matter if it is gambling? You obviously have some funds on a gambling site already, so that is not the problem I guess.

as far as i know, playing lottery is one of the gambling game but we sometime we do not realize it because its really fun. we bought for example 1000 lottery for cheap price and hoping that our number is out to be a winner.

if you ask will it be addictive? my answer is yes, if you only want to be a winner on that lottery. be careful, do not be so addictive. loss you money while you want and you can, and in the meantime, if you loss, don't regret it.