Naturalisation residency confusion

[MKC2009]

I received my ILR BRP yesterday. I have found out via this forum that I'm eligible for Naturalisation straight away after being granted ILR as a spouse of BC after 5-year residency and I was just looking at the application form.
Just wanted to know about 3-year residency period. Its strange that you have to spend 5-years to get ILR and 3-years residency for Naturalisation. It doesn't add up. I know if you're not married to British Citizen you'd need 5-year residency but that still doesn't make much sense.
One should be able to apply straight for Naturalisation after completing 5-year residency. I think it's just getting an extra fee from the applicant to apply for ILR.

Could someone clarify above for me please.

I thought employment was not a requirement for Naturalisation. I was thinking of applying for other jobs or maybe starting own small business. Will it have any effect on my Naturalisation application? Does one have to have a job to be eligible for employment? If I change employment whilst waiting for Naturalisation is that ok?
Can I use my manager and another 25-year old as referees?

[CR001]

The 3 year residency for a spouse of BC stems from years ago when a spouse visa was issued for 2 years plus one year on ILR,pre 8 July 2012. It is Harder to change nationality law than immigration rules.

Employment is not required to apply for citizenship.

[MKC2009]

Thanks you CR001. This does clear up. I understand now as naturalisation doesn’t come under immigration rules. Confusion cleared.

[MKC2009]

Do we upload scans of passport sized photos as well? Both sides with names at the back? Or is that not a requirement for online naturalisation application?