It depends
Few benefits of Accor plus travellers are
20 status nights so if you are chasing Accor gold status then you can leverage this
50% off in dining
Access to red hot rooms which gives access to upto 50% off
All accor silver tier so may be you can get some elite recognition for your upcoming stays.
The way I see it if you are planning to hit 10 nights this year , or 40 nights you can use this opportunity to get 20 status nights and get fast track upgrade to Gold or Platinum status with accor.
If you are not someone who falls in the above category then it's an offer which can be easily skipped.