It's highly dodgy!
If you're ever in doubt as to whether to trust claims made by marketers, remember the Fisher Price Rock n Play Sleeper, sold in the USA, marketed heavily over the last 10 years as a great sleeping place for your newborn. Responsible for over 50 deaths, they knew full well it didn't meet safety standards for safe sleep and yet only recalled when they were forced to.
Purflo are very careful in their wording because they want you to believe they are responsible. The problem is it makes me suspicious.
The fact that no deaths have ever been directly associated with that specific product is not really relevant information considering it has not been out for very long. It's a bit like Lisa selling Homer the anti-bear rock in the Simpsons, because "Look, there aren't any bears here, therefore it works!" The fact is that deaths have been associated with infant sleep nest type products, although which ones specifically is never released because there isn't a public case being made about it. Anecdotally I've also come across reports as well but they aren't made public. That is likely because a single event is a tragic accident, you need several instances of the same thing happening to say that it's a fault or danger inherent to a product, and if these deaths all happen in different countries then the numbers are not always being counted together.
Saying something "meets all relevant safety certifications" can be misleading too - the fact is, because it is not classed as a cot or Moses basket, there are no relevant safety certifications, so saying it's passed all of them is a bit like saying "with all due respect" when you're trying to insult somebody. It has passed certifications relating to loose threads and swallowable parts - not especially relevant for sleep. There is a lot of word salad and waffle on their website about all the testing they do but they never actually explain what they are testing for directly, they just vaguely allude to important-sounding bodies and regulations that are not directly relevant to their product. They have a whole thing about breathability and thermoregulation and somehow make it sound like they are saying breathability tests the chance of suffocation, which it doesn't. Breathability in terms of testing and certification only applies to thermoregulation and preventing overheating.
I completely get the point that babies don't like to sleep in completely open flat cots in a cold temperature room without covers and without an adult next to them on their backs. Absolutely. And I understand why people would look for a product that makes their baby more cosy to sleep. I would just say understand the risks. I choose to co-sleep with my newborns, and I've always found they need to be warmer than guidance suggests. I understand the risks are higher with both of these things (at least until 4 months of age) and I accept that.
One thing I will say is 13 years ago when I had DS1 all the threads on MN were "My baby won't sleep on his back. Is it really that risky to put him on his front?" And today they are "My baby won't sleep in a cot. Is it really that risky to add a Sleepyhead?" It's worth understanding that parents have always asked these questions and we know the risks of front sleeping, but we don't really know the risks of baby nests (except that they are essentially pillows, and we know not to use pillows). It's also worth remembering that the majority of babies will be absolutely fine even if you do decide to break the rules. We are talking about tiny chances here. Absolutely tiny. But I think it is worth talking about them, and I would always be suspicious if a company claims to be the "only" product that avoids a known risk associated with others.