At 17 weeks no I would not get one.
The problem with them is that you are not trained in interpreting the results, which means that you can be falsely reassured when you really should be seeking medical assistance ASAP. Or the other way, everything is fine but you can't find the heartbeat leading to distress, panic and potentially wasted time seeking reassurance.
I have used one, and I don't think they're terrible things to use in the first weeks, maybe week 10-20 or so, as long as you're aware of a few key things.
Only use it if you're totally on board with "if anything happened at this point there's no way of stopping it anyway" - and be honest with yourself, because that's a really hard thing to be on board with.
Understand that it can be tricky to use even with training and you're a total amateur using without training, so see it as an entertainment device rather than a medical one.
NEVER use it past the point that you've started feeling movement. Don't mess around with dopplers at that point. Just go in if you have concerns.
But in general, probably not the best idea. I don't know whether they should be banned as I quite liked using mine, but I do think on balance they probably cause more worry than reassurance.