For example, to "shoot some pictures during a wedding". A photographer does not just want to pick up the camera and take some half-size pictures, of course you want to shoot good pictures and in addition, you shoot in RAW format which should then be opened in a program and edited a bit before they are ready (and the pictures should also be sorted and selected which ones got the best of all hundreds of people caught).
It's not just about handing over the memory card. I think that when you do the job that is your profession, you want to deliver the same result, whether it is an unknown customer or a good friend. Especially since it also serves as a portfolio for future customers and is a receipt for the job you do.
There is also the idea that private individuals are not as willing to invest in certain things as companies might be. We may book a massage for close to a hundred Euro, and buy flowers or alcohol without blinking, but invest a sum in their interest or passion - it may not be as obvious. But sometimes people are aware of an intrinsic or inherent value - and in fact many people are actually willing to pay to get help with SEO, as an example.
But, this is your JOB! Your work and your life! Even if you love your job as a photographer, or love search optimization, it is still a source of income for you. That's what you feed on. If, on the other hand, you have another full-time job and are just pursuing a hobby, well then you may be more willing to set up and foot free because you may not take other assignments and do not see it as a business. But if, on the other hand, everyone you know suddenly wants you to come and photograph them, you might have to say no - or do a business.
In general, we also know that a work assignment will be better done and more professional if there is a price for it. Because even if you want to deliver your best self regardless, it feels more “for real” even if your friend pays for it. If you don't get paid, you might be thinking "oh, it's not that accurate ..." And ultimately charging for things allows others to understand the value of what you do. Paying is also a sign of your surroundings that you value your knowledge and that they should do so too.
You don't "just take some pictures" but you actually do a job that you spend a lot of hours learning and getting good at. When people pay you for your work, it means it can be prioritised as any work would be so with your friends and acquaintances who want help, you can prioritize work in the same way as your other assignments. If someone is willing to pay for the services you offer, then you can help them during your working hours - if, on the other hand, they want you to set up for free, maybe you need to prioritize it less and then maybe they never get help.