Why Would You Freeze Your Eggs?
For 1, a woman may wish to freeze her eggs if she needs to delay childbirth. This page explores several reasons why, for example, "Women who want or need to delay childbearing in order to pursue educational, career or other personal goals.". Additionally, it explores some basic explanations of the process, if you are interested. If a woman has doubts about her fertility in 10 years time (using your final sentence as an example), such as if she is recently diagnosed with cancer, or needs to finish education but is ready to be committed to having a baby in more than 9 months' time, then she may decide to freeze her eggs for a time when she is more suited to have a baby, using a time when her body is more suited to producing eggs.
Does Freezing Have Adverse Effects?
As for your second question, the same page does mention successfully freezing an embryo for 10 years at -196 degrees Celsius, with no adverse effects on the eventual birth.
Regardless, exploring the risks reveals that the decision on whether the practice is seen as positive or negative is still on the fence - different parties argue for different opinions, as there appears to be no objective truth about proven adverse affects.
The risks described by this clinic are worth considering, albeit minimal compared to a risk of malformed children, however, it is still a popular choice, albeit put forward as 'experimental'. This study (2010, Rudick et al) showed how, in the US, cryopreservation was already being offered in 283 of 442 fertility clinics surveyed. 1/3 of the reasons for the choice was for women with cancer, and the other 2/3 was for women with 'advancing maternal age'.
The ACOG (American College of Obstetricians and Gynecologists), in 2013, stated that they do not endorse freezing of eggs 'for the sole purpose of circumventing reproductive aging in healthy women', however, the ASRM (American Society for Reproductive Medicine) lifted its label as being 'experimental' in 2012. The previously linked article describes a study conducted by the ASRM, which 'reviewed data from four randomized controlled trials and various observational studies that compared fertilization rates, embryo implantation rates and pregnancy rates of fresh eggs versus eggs that were frozen', and 'showed no increase in birth defects, developmental disorders or chromosomal abnormalities when in vitro fertilization cycles were conducted with frozen eggs, leading the society to declare the technique effective and safe'.
Your question is a slightly broad one, and can be answered by the subjective choice of the woman/women involved, however the ASRM still stresses that "we should proceed cautiously in using this as an elective technique", by making a clear line between 'need' and 'want'. However, there is no evidence to show that rates of abnormality are any higher using this method, but considering it is still a fairly new practice that is being marketed as a choice rather than a medical treatment, there is skepticism in the air around whether marketing scientific and medical designs as a mere 'choice' for older women will lead to this technology becoming better or worse.
Additionally, about your comment of it being 'less expensive', this website shows that the average cost of in vitro fertilization in the U.S. is currently about 10,000 - 20,000 USD, whereas the first website I linked (here) estimates the cost at about 10,000 USD to undergo an egg freezing cycle. Although, the prices will change from clinic to clinic. Regardless, the prices are still similar, and the choice lies in the woman choosing to pay and freeze her eggs if, for example, she has recently been diagnosed with cancer, or fears she will not be fertile in 5+ years time.
I hope this answer has been sufficient in answering your questions, and if you have any more questions, feel free to ask me :)