Protection of formulae : How often have you forgotten to protect the cell contains the formula that took you hours to test and perfect. It takes one instance of honest human error, and that formula is gone.
You'll need to find a way to make your spreadsheet accessible. You can build a website, which will require paying for a domain, hosting, site security, dealing with an internet transaction service, graphic design, content for the website, marketing your website, Search Engine Optimization, and all the other madness that comes with managing a site.
A popular category of ready-made spreadsheets mentioned earlier, is 'Spreadsheets for Actors'. 'Spreadsheets for Actors' includes sets of programmed spreadsheets that are especially designed for professionals in the entertainment industry, from Actors to Producers. The spreadsheets under 'Spreadsheets for Actors' range from facilitating the managing of budgets to keeping track of income emerging from many sources.
When VisiCalc hit the scene back in the eighties (in the last century), the relatively small group of Apple II users went crazy. It was like manna from heaven for the poor accountants, scientists and engineers who were used to filling in enormous analysis sheets with a pencil. Now, they could use VisiCalc to do the same task, AND calculate the result automatically.