Being a TA has helped throughout my Ph.D. I would highly recommend becoming a TA for the following reasons.
- You get paid.
- You learn teaching skills
- You strengthen your knowledge.
- It's good for the C.V.
First and foremost you need to fund your life and studies. Although being a TA might not offer the greatest of pay and may take a lot of time. It does seem to pay reasonably well for the amount of effort you have to put in.
Secondly but possibly one of the most underrated things about being a TA. You learn to communicate, and you learn to communicate and learn how to teach.
By communicate, I don't mean just how to improve your English, but how to engage with students. Teaching skills are great, and if you want to go into academia or wish to go in a role where you have to explain concepts to others this will come in handy.
OK, you're teaching at undergrad level. So you may think you know everything. You may actually be surprised that some undergrads may ask some really advanced level questions. Also you may find yourself recapping on some content which you just swept over in your own undergraduate degree. Recovering content, you could find you have a better understanding of it.
Since being a TA. I have had several offers to teach in academic and commercial organisations, and have become a visiting lecturer at another institution based on some of my TA activities.
In terms of cons:
Teaching, marking etc takes time. You may only be teaching for an hour of time, but actually its 4 hours worth of work. From preparing slides, teaching, marking coursework, meetings about students progress with academic staff etc.
I would suggest you give it a go, its only 10 hours after all. If you find it's too much you can always say that it's too much and you will be unable to continue being a TA as you feel your studies are suffering.
Best of luck and I hope this has been of some help.