nervous if baby will be with you all the time, including naps, then I would say do not worry about getting one. Mine always sleep and nap in their cots in their room, so it suited us. I recommend you read the reviews on Amazon, and make up your own mind. It is only any good really until they can roll over, so about 6months. The audio quality is not that great. We swapped back to the trusty BT monitor at 6 months. That one has been used non stop for over 6years, and the plastic on the buttons has perished, so we need to poke things into it to turn it on and off!
A while back at work my colleagues were laughing about the stupidity of movement sensors. I just kept my gob shut.
I say if something helps you worry a little less, sleep a little better, then why not. Some folk think matching nursery bedding is worth the expense, and travel systems costing over 1K... It is a very personal choice IMO.