More disk space may be needed depending upon the application file storage requirements. This is a different situation from the almost mandatory upgrade from MS-DOS 6.0 to 6.2. DOS 6.0 disk compression was faulty. The current environment, on the other hand, of Windows 3.1 or 3.11 running over DOS 6.2 is relatively stable. As a result, the general release of Windows 95 is several months later than first predicted.
Nobody really knows if the bugs have been fixed properly, yet, though.
Just because we can't buy a new computer without Windows 95 is no justification to put Windows 95 on all our old ones, at least not yet.