Firstly because it usually has only a month's notice period, with no set dates, so no hanging around waiting for October 31 to hand in your notice. If you see a teaching job advertised to start soon, you can apply.
Secondly, because it gives you a lot of CPD, because you are watching other teachers on many occasions. You see what to do - and what NOT to do - in many different learning situations.
I always suggest that when you start as a TA, you keep a Learning Diary, write in it every day, and mention it in a future job application when you talk about how your teaching skills have developed during your period as a TA.
But less stress, less work also adds up to considerably less pay, and this is something that you should be aware of.
A post as a TA, a HTLA or a CS is generally considered part-time because you do not work the hours and the weeks that are worked by a full-time member of administrative staff.elsewhere in the County.
N.B. - something that you may not have realised:
This may also mean that you actually do not get the salary that is advertised, as it will almost certainly be advertised pro-rata.
The TA, CS and HLTA wages are calculated as are the office staff in LEA offices, basically. So there is double part-time factored in when they give you the salary in an advert, then they add pro-rata.
Firstly, as I have said, it is pro-rata for weeks of the year. You do not work the 52 weeks minus holiday entitlement. You only work when schools are open.
Secondly, it is pro-rata for hours per week. You do not work the 38 or 40 or whatever it is hours per week. 8.30 - 3.30, minus lunch, is probably only 30 or so hours a week.
They therefore reduce the advertised salary twice, once for fewer weeks and once for fewer hours.
As you can guess, this can reduce the money substantially.
Let us suppose that it is advertised as £15,000, pro-rata. N.B. This is a very approximate calculation, don't take it as gospel truth!
Reduce it by the weeks: 39 working weeks plus 4 weeks holiday pay. 43/52.
£15,000 x (43/52) = £12,404
Reduce it by the hours: 30 hours instead of 38 per week. 30/38
£12,404 x (30/38) = £9,793
So a salary for a TA, working 8.30-3.30 in term time, advertised as £15,000 pro-rata actually means £9,793.
Before tax and other deductions . . .
A Big Warning to everyone applying for TA posts: ask, ask ASK what the salary will actually be after they have factored in the two pro-ratas.
It's also a good idea to buy some book to give general guidance about your role. Here's one possibility that I like; you can find others on Amazon.