There are great points on SEO and accessibility, the latter which is sadly often an afterthought. However, the author does shoot themselves in the foot a little when the first "typical" example they offer is a div tag with an inline style="background-image: ...". It negates the the preceding point made on how it is bad for CMSes and CDNs and shackles them. Finally, advocating a polyfill to support the small number of users that don't need object-fit could potentially add more render-blocking for everyone if not done carefully.