Do not acknowledge the snapchat as any legitimate form of asking.
Voluntary redundancy as far as I'm aware would need to be offered to everyone, likely as part of the standard redundancy process.
Snapchat isn't part of that. Whether there is malicious intent or not, I can see if you agree via snapchat... or start asking about it following it, that they will see more as a candidate for, and have a bias when scoring etc so you are redundant, without it actually being considered as voluntary iyswim...and therefore you miss out on any benefits it may or may not confer.
I'm no employment lawyer or HR though. Just it sounds completely unprofessional to proceed through such as delicate and upsetting process.
As to whether you should take it...its a personal choice. Would you get any additional benefit from volunteering (financially that is)?
Some people take it to use the money to start businesses, spend time with family etc. And feel it better to be paid to leave than quitting in normal circumstances. But I think those people have already been weighing that up in their heads, and redundancy comes along as the last excuse to take the leap.
Do you see yourself staying in the company, or are you already planning to move on? Perhaps if you've applied for roles already and could get something lined up, you might as well be paid to leave.
But otherwise, can you afford it? There is a very real prospect of being out of work for some time at the moment I think...you obviously dont get to choose if you're a compulsory redundancy, but part of the process lets you fight your corner as to why you should stay. It's always important to remember it's the role that's redundant not you per see, you may be redeployed or have your role changed. If there are multiple people in your role, others can take it and make you safe.