Is it right for a company to expect you to use your personal phone number when you work from home?

I’d get a disposable Google Voice number. That would allow for my separation of work and life

Since the beginning of the pandemic (and the start of a real WFH policy), we've been using Microsoft Teams Phone functionality (incoming and outgoing calls).

So, anyone trying to reach me at my telephone work number, including my extension, will end up connecting through my Teams Client.   I can just click to answer or not.

This cuts the need of asking our employees to use their phone for conducting their activities.   Of course, with internal colleagues, Teams is used for this.   But to call a provider or anyone, it's quite convenient to do this using Teams itself.

For me, I would rather have just one device that I need to worry about versus carrying two phones, which I did for a long time.

Employee can decide to WFH and decide if they want to user their mobile devise for work purposes.

As always, "it depends".  From both the employee and employer perspective, expectations must be set from the start.  An argument can be made from both directions and both have merits.  Employers may not want employees to use their personal number.  Employers may not want to provide the resource to use a corporate number.  Employees may not want to use their personal number.  Employees may be most comfortable using their personal number.  It's all about perspective and expectations.  There is no single "right" answer.  However, it is "trivial" for both an employer to provide a corporate number and for an employee to establish a new phone number (can even use a free service like Google Voice) so that everyone wins.

I'll also add, if this is an area where employee/employer "butt heads" then it's likely not a good match and there will certainly be future clashes.