I am in a pretty similar boat to you in that I applied more out of a having a genuine interest in DS / ML rather than necessarily wanting to pivot my existing career directly into the space. Being able to take it alongside my existing job is very appealing. I wouldn’t underestimate the number of hours the course will demand of your week though, I reckon I’ll be studying in evenings and both days of the weekend if I get on to the course.
I also agree with you in that I see it as an opportunity to futureproof myself. I would, however, be hesitant to embark upon it on if you would be starting without either an elementary understanding of the underlying maths (linear algebra, calculus) or programming – I think it’d be quite a challenge to get up to speed on both the theoretical (maths) side of DS / ML and the practical (programming) side at the same time.
FYI if you are interested in applying, I would get your application submitted ASAP. With the prior year’s course being deferred due to COVID-19 I’m not sure how many spaces are available for those newly applying this year. Even though it’s online I presume there is a cap on the number of applicants they can take. I applied back in November and haven’t heard anything from Imperial yet despite chasing them a few times with follow-up emails.
You should also look at Bath, who offer a similar online MSc in Artificial Intelligence, and the University of Georgia over in the US, who offer an Online Masters in Science Computer Science (OMSCS) which has DS / ML modules, is more flexible in terms of time to completion, and is significantly cheaper than the two UK options.