Yes tennis shoes are good for walking in.
I wear tennis shoes for walking and I even run and jog in tennis shoes and they are very comfortable for me.
I don't even play tennis and wear tennis shoes and a lot of people walk and run and jog and just go about their day wearing tennis shoes even though they may never play tennis.
A good pair of tennis shoes should last for 5 to 10 years depending on how much walking or jogging etc you do.
I have a pair of 10 year old tennis shoes that are still in pretty good condition.
During the summer though I like to wear Sandals or Crocks shoes because they allow my feet to breathe because I get pretty sweaty and my feet get rashes and they become itchy during the summertime.
But tennis shoes are good for walking during the fall, and spring and winter months.