I think it was a little bit of both! He was good filler, but he was also very popular, as was the Boston Post in general (it had one of the countries highest circulation rates) and postcards and photos of Hindy were printed and given away, eventually thousands a day were printed. Lots of people sent in gifts to Hindy, catnip being a very popular one. He appeared at different events around town. Hindy’s name was used to support various local charities and fundraisers. He was a favourite with the Child’s restaurant in the main floor of the Post building, where staff fed him scraps daily. Sadly in 1923 Hindy was attacked by a dog and succumbed to his wounds after an infection. You can still find the photographs of Hindy online today, there are some selling on ebay and sites like rubylane for $20-50 each! Hindy’s still a hot commodity! 

I wish I could post Hindy’s obituary, I bet it was great, but newspapers.com Boston Post archives end in 1921 and I can’t find any other sources for it online.