Intel Sunsets Pentium And Celeron For Laptops Following Branding Update
Intel says that the reason for the change is to "simplify the purchasing experience for customers." It's a little difficult to imagine how that might be the case, but perhaps the company believes that simply relying on model numbers will be easier than having to know whether a Pentium Silver or Celeron is better.

Historically, besides Xeons, Intel had "Core" and "Atom" as its two leading processor families, but the company discarded the Atom branding without terminating the technology, leading to the expansion of the Pentium and Celeron branding to include processors based on both its "little cores"—that is, processors formerly known as Atom—as well as its "big cores," the same CPU technology included in "Core" series chips.
Before that, "Pentium" and "Celeron" chips were generally just extremely cut-down and cost-reduced forms of the mainstream desktop and laptop CPUs. The move to fold Atom-family chips into the Pentium and Celeron families wrought much confusion as to what you were actually buying when you bought a Pentium or Celeron processor. Intel tried to amend this with the awkward "Pentium Gold" and "Pentium Silver" branding, but consumers found that even more confusing.
Ultimately this move, while laughable on the face of things, is probably a good thing for Intel. Just like AMD did with its recent decoder ring exercise, Intel can take this opportunity to use processor model numbers to clearly define what exactly is in its mobile CPUs. We don't know that the company will do that, but we can dream.