Either way, I'm effectively leaving the company on good terms, so why would the company only offer these benefits if I am formally fired?
Notice weeks are usually not a kindness, but rather a legal obligation. The law can stipulate that the "surprised" party (i.e. those who did not initiate the termination) is entitled to a grace period to be able to prepare for said termination.
The absence of such a notice period would put a significant impact on the surprised party, and it would disproportionately affect an employee (whose sole source of income has disappeared) compared to a company (who loses one staff member out of presumably many, but not their source of income). Because of that, company-initiated terminations (where the employee is the surprised party) can require a longer notice period so as to ensure that the employee is able to prepare accordingly.
In my local culture (Belgium), the notice period/severance pay can be up to twice/thrice as long if a company fires you, compared to you handing in your resignation.
Doesn't this add additional costs to the company, such as having to cover unemployment claims if I were to seek unemployment benefits?
Saving money does not seem to be the company's main goal here, as they are already aware of how firing you costs them more money (severance pay). So your question may be valid but seems to be irrelevant to judge the company's current goal.
What are the potential ramifications to me if I decide to take their offer of being terminated?
The main issue with being terminated is that future employers are likely to assume you were fired for not being an adequate employee. That is not provably correct, but the inference is often made.
Your manager offering to write that letter stating mutual agreement about the termination somewhat alleviates that concern, but not fully.
An employer who would already have assumed negative things about you as an employee based on being fired, may also assume that this letter was written to try and hide that fact, and thus ignore the letter (or even use it as further proof that there is something undesirable about you as an employee).
But I can't make any guarantees here. The letter might sway people, or it might not.
There is one more avenue to consider: what is the company getting out of this?
It's not impossible that this is pure kindness, but it's also possible that the company is getting something from it. There's two options I can think of:
- They could want/need the longer notice period
If the notice period for termination is longer than that for resignation, they could be trying to ensure you have to stay longer than you would otherwise be required to be.
- They're trying to hide that you chose to quit, presumably from other employees
I've worked at companies where employee morale was consistently low, and if a liked employee quits, it may spur others on to do the same. Or at least the company fears that this may happen and would rather pay you severance than risk multiple employees quitting.
Is that likely in your case? I can't say. But I've seen this happen in other cases.
At face value, it seems that the company is showing you a kindness by giving you severance. With the letter in hand, there may be little to no consequences (that negatively impact your life) from having been fired instead of resigning.