Spikes

I'd ask you a question: Why do you have Spikes? Why is Product Backlog Refinement insufficient?

Consider that there is no timebox on Product Backlog Refinement. The Scrum Guide states that refinement "usually consumes no more than 10% of the capacity of the Development Team" but does not put any firm limits. If you consider that a Spike is just an exploration into better understanding proposed work, how is this any different than refinement of the Product Backlog?

Are spikes supposed to be pointed?

Do you have a lot of them in a Sprint? Is it even possible for the team to estimate them, as opposed to just time-boxing them in refinement? Do you need transparency over how much work to complete spikes remains?

We have spikes, and always give them points. It will not only make velocity more transparent, but als work as a measure of progress into the unknown.

And I say it like this, because spikes for me are journeys into the unknown. Unknown products, features or even business cases, where the team and PO needs to get more of a bearing of what to expect, incorporate into their whishes and vision.

The benifit of a spike is that not the whole team is held up during refinement with things of an investigative nature, and things can be explored and shared in an effective manner

Why does an activity which is just a "formalized" statement of work needed in order to refine something in the Product Backlog need to be accounted for at all?  Do you create items in your Sprints for all of your refinement activities and point them? In my opinion, the only reason to use a spike is to provide transparency to the fact that some portion of the Development Team will not be able to work on items supporting the Sprint Goal and that velocity may be impacted.  I actually prefer to not use spikes at all and just have the team realize that there is need for some people to work on investigation. Discussion in every Daily Scrum can prevent too much time being used.  I see spikes as a means to create process where process isn't really needed.  But that is only my opinion.

Is there any real value to creating an item in the Product or Sprint Backlogs for the activities related to refinement?